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Vulnerability details: VCID-myz5-wsnu-u7a5
Vulnerability ID VCID-myz5-wsnu-u7a5
Aliases CVE-2026-34519
GHSA-mwh4-6h8g-pg8w
Summary aiohttp: aiohttp: Header injection vulnerability via reason parameter
Status Published
Exploitability 0.5
Weighted Severity 4.8
Risk 2.4
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-1286 Improper Validation of Syntactic Correctness of Input
CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
System Score Found at
cvssv3 5.3 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34519.json
epss 0.00053 https://api.first.org/data/v1/epss?cve=CVE-2026-34519
cvssv3.1 3.7 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv4 2.7 https://github.com/aio-libs/aiohttp
generic_textual LOW https://github.com/aio-libs/aiohttp
cvssv4 2.7 https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
generic_textual LOW https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
ssvc Track https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
cvssv4 2.7 https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
generic_textual LOW https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
ssvc Track https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
cvssv4 2.7 https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
generic_textual LOW https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
ssvc Track https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
cvssv4 2.7 https://nvd.nist.gov/vuln/detail/CVE-2026-34519
generic_textual LOW https://nvd.nist.gov/vuln/detail/CVE-2026-34519
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34519.json
https://api.first.org/data/v1/epss?cve=CVE-2026-34519
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-34519
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/aio-libs/aiohttp
https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
https://nvd.nist.gov/vuln/detail/CVE-2026-34519
1132582 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1132582
2454100 https://bugzilla.redhat.com/show_bug.cgi?id=2454100
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34519.json
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

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N 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)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U Found at https://github.com/aio-libs/aiohttp
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)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U Found at https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
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)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-02T15:40:04Z/ Found at https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U Found at https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
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)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-02T15:40:04Z/ Found at https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U Found at https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
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)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-02T15:40:04Z/ Found at https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8w
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U Found at https://nvd.nist.gov/vuln/detail/CVE-2026-34519
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)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.17029
EPSS Score 0.00053
Published At June 5, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:31:43.449998+00:00 RedHat Importer Import https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-34519.json 38.6.0