{"url":"http://public2.vulnerablecode.io/api/packages/64096?format=json","purl":"pkg:pypi/matrix-sydent@2.0.0","type":"pypi","namespace":"","name":"matrix-sydent","version":"2.0.0","qualifiers":{},"subpath":"","is_vulnerable":true,"next_non_vulnerable_version":"2.5.6","latest_non_vulnerable_version":"2.5.6","affected_by_vulnerabilities":[{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/218130?format=json","vulnerability_id":"VCID-2t4j-nm56-tkgm","summary":"Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to memory exhaustion and denial of service. Sydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service. This affects any server which accepts registration requests from untrusted clients. This issue has been patched by releases 89071a1, 0523511, f56eee3. As a workaround request sizes can be limited in an HTTP reverse-proxy. There are no known workarounds for the problem with overlarge responses.","references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29430","reference_id":"","reference_type":"","scores":[{"value":"0.01367","scoring_system":"epss","scoring_elements":"0.80614","published_at":"2026-06-11T12:55:00Z"},{"value":"0.01367","scoring_system":"epss","scoring_elements":"0.80674","published_at":"2026-06-12T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29430"},{"reference_url":"https://github.com/matrix-org/sydent","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent"},{"reference_url":"https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7"},{"reference_url":"https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d"},{"reference_url":"https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428"},{"reference_url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0"},{"reference_url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9"},{"reference_url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-21.yaml","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-21.yaml"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29430","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29430"},{"reference_url":"https://pypi.org/project/matrix-sydent","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"value":"8.7","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://pypi.org/project/matrix-sydent"},{"reference_url":"https://pypi.org/project/matrix-sydent/","reference_id":"","reference_type":"","scores":[],"url":"https://pypi.org/project/matrix-sydent/"},{"reference_url":"https://github.com/advisories/GHSA-wmg4-8cp2-hpg9","reference_id":"GHSA-wmg4-8cp2-hpg9","reference_type":"","scores":[{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-wmg4-8cp2-hpg9"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/64100?format=json","purl":"pkg:pypi/matrix-sydent@2.3.0","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-qv9q-g8dy-wuda"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:pypi/matrix-sydent@2.3.0"}],"aliases":["CVE-2021-29430","GHSA-wmg4-8cp2-hpg9","PYSEC-2021-21"],"risk_score":4.0,"exploitability":"0.5","weighted_severity":"8.0","resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-2t4j-nm56-tkgm"},{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/218131?format=json","vulnerability_id":"VCID-6ydp-qbur-zkcw","summary":"Sydent is a reference Matrix identity server. Sydent can be induced to send HTTP GET requests to internal systems, due to lack of parameter validation or IP address blacklisting. It is not possible to exfiltrate data or control request headers, but it might be possible to use the attack to perform an internal port enumeration. This issue has been addressed in in 9e57334, 8936925, 3d531ed, 0f00412. A potential workaround would be to use a firewall to ensure that Sydent cannot reach internal HTTP resources.","references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29431","reference_id":"","reference_type":"","scores":[{"value":"0.00303","scoring_system":"epss","scoring_elements":"0.53976","published_at":"2026-06-11T12:55:00Z"},{"value":"0.00303","scoring_system":"epss","scoring_elements":"0.54101","published_at":"2026-06-12T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29431"},{"reference_url":"https://github.com/matrix-org/sydent","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent"},{"reference_url":"https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a"},{"reference_url":"https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3"},{"reference_url":"https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a"},{"reference_url":"https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f"},{"reference_url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0"},{"reference_url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4"},{"reference_url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-22.yaml","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"value":"6.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-22.yaml"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29431","reference_id":"","reference_type":"","scores":[{"value":"7.7","scoring_system":"cvssv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is a reference matrix identity server. A malicious user could abuse Sydent to send out arbitrary emails from the Sydent email address. This could be used to construct plausible phishing emails, for example. This issue has been fixed in 4469d1d.","references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29432","reference_id":"","reference_type":"","scores":[{"value":"0.0025","scoring_system":"epss","scoring_elements":"0.48626","published_at":"2026-06-11T12:55:00Z"},{"value":"0.0025","scoring_system":"epss","scoring_elements":"0.48763","published_at":"2026-06-12T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29432"},{"reference_url":"https://github.com/matrix-org/sydent/commit/4469d1d42b2b1612b70638224c07e19623039c42","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/4469d1d42b2b1612b70638224c07e19623039c42"},{"reference_url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/releases/tag/v2.3.0"},{"reference_url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-mh74-4m5g-fcjx","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-mh74-4m5g-fcjx"},{"reference_url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-23.yaml","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-23.yaml"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29432","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29432"},{"reference_url":"https://pypi.org/project/matrix-sydent","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"6.9","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://pypi.org/project/matrix-sydent"},{"reference_url":"https://pypi.org/project/matrix-sydent/","reference_id":"","reference_type":"","scores":[],"url":"https://pypi.org/project/matrix-sydent/"},{"reference_url":"https://github.com/advisories/GHSA-mh74-4m5g-fcjx","reference_id":"GHSA-mh74-4m5g-fcjx","reference_type":"","scores":[{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-mh74-4m5g-fcjx"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/64100?format=json","purl":"pkg:pypi/matrix-sydent@2.3.0","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-qv9q-g8dy-wuda"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:pypi/matrix-sydent@2.3.0"}],"aliases":["CVE-2021-29432","GHSA-mh74-4m5g-fcjx","PYSEC-2021-23"],"risk_score":3.1,"exploitability":"0.5","weighted_severity":"6.2","resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-83jx-ejpc-1kdq"},{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/218128?format=json","vulnerability_id":"VCID-ckar-nhrw-uuhn","summary":"### Impact Missing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. ### Patches Fixed by 3175fd3. ### Workarounds There are no known workarounds. ### References n/a ### For more information If you have any questions or comments about this advisory, email us at security@matrix.org.","references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29433","reference_id":"","reference_type":"","scores":[{"value":"0.00281","scoring_system":"epss","scoring_elements":"0.51787","published_at":"2026-06-11T12:55:00Z"},{"value":"0.00281","scoring_system":"epss","scoring_elements":"0.51917","published_at":"2026-06-12T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2021-29433"},{"reference_url":"https://github.com/matrix-org/sydent","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent"},{"reference_url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da"},{"reference_url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553"},{"reference_url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-24.yaml","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-24.yaml"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29433","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29433"},{"reference_url":"https://pypi.org/project/matrix-sydent","reference_id":"","reference_type":"","scores":[{"value":"4.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"value":"5.3","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://pypi.org/project/matrix-sydent"},{"reference_url":"https://pypi.org/project/matrix-sydent/","reference_id":"","reference_type":"","scores":[],"url":"https://pypi.org/project/matrix-sydent/"},{"reference_url":"https://github.com/advisories/GHSA-pw4v-gr34-2553","reference_id":"GHSA-pw4v-gr34-2553","reference_type":"","scores":[{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-pw4v-gr34-2553"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/64100?format=json","purl":"pkg:pypi/matrix-sydent@2.3.0","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-qv9q-g8dy-wuda"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:pypi/matrix-sydent@2.3.0"}],"aliases":["CVE-2021-29433","GHSA-pw4v-gr34-2553","PYSEC-2021-24"],"risk_score":3.1,"exploitability":"0.5","weighted_severity":"6.2","resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-ckar-nhrw-uuhn"},{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/131884?format=json","vulnerability_id":"VCID-qv9q-g8dy-wuda","summary":"Sydent is an identity server for the Matrix communications protocol. Prior to version 2.5.6, if configured to send emails using TLS, Sydent does not verify SMTP servers' certificates. This makes  Sydent's emails vulnerable to interception via a man-in-the-middle (MITM) attack. Attackers with privileged access to the network can intercept room invitations and address confirmation emails. This is patched in Sydent 2.5.6. When patching, make sure that Sydent trusts the certificate of the server it is connecting to. This should happen automatically when using properly issued certificates. Those who use self-signed certificates should make sure to copy their Certification Authority certificate, or their self signed certificate if using only one, to the trust store of your operating system. As a workaround, one can ensure Sydent's emails fail to send by setting the configured SMTP server to a loopback or non-routable address under one's control which does not have a listening SMTP server.","references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2023-38686","reference_id":"","reference_type":"","scores":[{"value":"0.00064","scoring_system":"epss","scoring_elements":"0.20259","published_at":"2026-06-11T12:55:00Z"},{"value":"0.00064","scoring_system":"epss","scoring_elements":"0.20435","published_at":"2026-06-12T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2023-38686"},{"reference_url":"https://github.com/matrix-org/sydent","reference_id":"","reference_type":"","scores":[{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/matrix-org/sydent"},{"reference_url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2023-139.yaml","reference_id":"","reference_type":"","scores":[{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2023-139.yaml"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2023-38686","reference_id":"","reference_type":"","scores":[{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-38686"},{"reference_url":"https://peps.python.org/pep-0476","reference_id":"","reference_type":"","scores":[{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://peps.python.org/pep-0476"},{"reference_url":"https://github.com/matrix-org/sydent/commit/1cd748307c6b168b66154e6c4db715d4b9551261","reference_id":"1cd748307c6b168b66154e6c4db715d4b9551261","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track*","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:T/P:M/B:A/M:M/D:R/2024-10-08T17:45:32Z/"}],"url":"https://github.com/matrix-org/sydent/commit/1cd748307c6b168b66154e6c4db715d4b9551261"},{"reference_url":"https://github.com/matrix-org/sydent/pull/574","reference_id":"574","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track*","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:T/P:M/B:A/M:M/D:R/2024-10-08T17:45:32Z/"}],"url":"https://github.com/matrix-org/sydent/pull/574"},{"reference_url":"https://github.com/python/cpython/issues/91826","reference_id":"91826","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track*","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:T/P:M/B:A/M:M/D:R/2024-10-08T17:45:32Z/"}],"url":"https://github.com/python/cpython/issues/91826"},{"reference_url":"https://github.com/advisories/GHSA-p6hw-wm59-3g5g","reference_id":"GHSA-p6hw-wm59-3g5g","reference_type":"","scores":[{"value":"CRITICAL","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-p6hw-wm59-3g5g"},{"reference_url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-p6hw-wm59-3g5g","reference_id":"GHSA-p6hw-wm59-3g5g","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"value":"9.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"},{"value":"CRITICAL","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"CRITICAL","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track*","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:T/P:M/B:A/M:M/D:R/2024-10-08T17:45:32Z/"}],"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-p6hw-wm59-3g5g"},{"reference_url":"https://peps.python.org/pep-0476/","reference_id":"pep-0476","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:A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