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Vulnerability details: VCID-y5ke-uj7u-rydk
Vulnerability ID VCID-y5ke-uj7u-rydk
Aliases CVE-2018-1000656
GHSA-562c-5r94-xh97
PYSEC-2018-66
Summary The Pallets Project flask version Before 0.12.3 contains a CWE-20: Improper Input Validation vulnerability in flask that can result in Large amount of memory usage possibly leading to denial of service. This attack appear to be exploitable via Attacker provides JSON data in incorrect encoding. This vulnerability appears to have been fixed in 0.12.3. NOTE: this may overlap CVE-2019-1010083.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-20 Improper Input Validation
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 7.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2018-1000656.json
epss 0.00575 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
epss 0.00583 https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
cvssv3 3.3 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1 7.5 https://github.com/advisories/GHSA-562c-5r94-xh97
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-562c-5r94-xh97
cvssv4 8.7 https://github.com/advisories/GHSA-562c-5r94-xh97
generic_textual HIGH https://github.com/advisories/GHSA-562c-5r94-xh97
cvssv3.1 7.5 https://github.com/pallets/flask
cvssv4 8.7 https://github.com/pallets/flask
generic_textual HIGH https://github.com/pallets/flask
cvssv3.1 7.5 https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
cvssv4 8.7 https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
generic_textual HIGH https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
cvssv3.1 7.5 https://github.com/pallets/flask/pull/2691
cvssv4 8.7 https://github.com/pallets/flask/pull/2691
generic_textual HIGH https://github.com/pallets/flask/pull/2691
cvssv3.1 7.5 https://github.com/pallets/flask/releases/tag/0.12.3
cvssv4 8.7 https://github.com/pallets/flask/releases/tag/0.12.3
generic_textual HIGH https://github.com/pallets/flask/releases/tag/0.12.3
cvssv3.1 7.5 https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
cvssv4 8.7 https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
generic_textual HIGH https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
cvssv3.1 7.5 https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
cvssv4 8.7 https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
generic_textual HIGH https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
cvssv4 8.7 https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
cvssv3.1 7.5 https://security.netapp.com/advisory/ntap-20190221-0001
cvssv4 8.7 https://security.netapp.com/advisory/ntap-20190221-0001
generic_textual HIGH https://security.netapp.com/advisory/ntap-20190221-0001
cvssv3.1 7.5 https://usn.ubuntu.com/4378-1
cvssv4 8.7 https://usn.ubuntu.com/4378-1
generic_textual HIGH https://usn.ubuntu.com/4378-1
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2018-1000656.json
https://api.first.org/data/v1/epss?cve=CVE-2018-1000656
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-1000656
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/advisories/GHSA-562c-5r94-xh97
https://github.com/pallets/flask
https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
https://github.com/pallets/flask/pull/2691
https://github.com/pallets/flask/releases/tag/0.12.3
https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
https://security.netapp.com/advisory/ntap-20190221-0001
https://security.netapp.com/advisory/ntap-20190221-0001/
https://usn.ubuntu.com/4378-1
https://usn.ubuntu.com/4378-1/
1623131 https://bugzilla.redhat.com/show_bug.cgi?id=1623131
CVE-2018-1000656 https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
RHSA-2020:0870 https://access.redhat.com/errata/RHSA-2020:0870
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2018-1000656.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/advisories/GHSA-562c-5r94-xh97
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/advisories/GHSA-562c-5r94-xh97
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pallets/flask
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/pallets/flask
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/pallets/flask/commit/b178e89e4456e777b1a7ac6d7199052d0dfdbbbe
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pallets/flask/pull/2691
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/pallets/flask/pull/2691
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pallets/flask/releases/tag/0.12.3
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/pallets/flask/releases/tag/0.12.3
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://github.com/pypa/advisory-database/tree/main/vulns/flask/PYSEC-2018-66.yaml
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://lists.debian.org/debian-lts-announce/2019/08/msg00025.html
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: 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 Found at https://nvd.nist.gov/vuln/detail/CVE-2018-1000656
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://security.netapp.com/advisory/ntap-20190221-0001
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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adjacent_network

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Vector: 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 Found at https://security.netapp.com/advisory/ntap-20190221-0001
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://usn.ubuntu.com/4378-1
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

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Vector: 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 Found at https://usn.ubuntu.com/4378-1
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

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Exploit Prediction Scoring System (EPSS)
Percentile 0.68842
EPSS Score 0.00575
Published At April 29, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:41:48.523454+00:00 Pypa Importer Import https://github.com/pypa/advisory-database/blob/main/vulns/flask/PYSEC-2018-66.yaml 38.0.0