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Vulnerability details: VCID-dq4c-cvs1-9qce
Vulnerability ID VCID-dq4c-cvs1-9qce
Aliases CVE-2026-41305
GHSA-qx2v-qp2m-jg93
Summary PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Versions prior to 8.5.10 do not escape `</style>` sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML `<style>` tags, `</style>` in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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 6.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-41305.json
epss 0.00011 https://api.first.org/data/v1/epss?cve=CVE-2026-41305
epss 0.00011 https://api.first.org/data/v1/epss?cve=CVE-2026-41305
epss 0.00011 https://api.first.org/data/v1/epss?cve=CVE-2026-41305
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-qx2v-qp2m-jg93
cvssv3.1 6.1 https://github.com/postcss/postcss
generic_textual MODERATE https://github.com/postcss/postcss
cvssv3.1 6.1 https://github.com/postcss/postcss/releases/tag/8.5.10
generic_textual MODERATE https://github.com/postcss/postcss/releases/tag/8.5.10
ssvc Track https://github.com/postcss/postcss/releases/tag/8.5.10
cvssv3.1 6.1 https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
cvssv3.1_qr MODERATE https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
generic_textual MODERATE https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
ssvc Track https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
cvssv3.1 6.1 https://nvd.nist.gov/vuln/detail/CVE-2026-41305
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2026-41305
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-41305.json
https://api.first.org/data/v1/epss?cve=CVE-2026-41305
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-41305
https://github.com/postcss/postcss
https://nvd.nist.gov/vuln/detail/CVE-2026-41305
2461366 https://bugzilla.redhat.com/show_bug.cgi?id=2461366
8.5.10 https://github.com/postcss/postcss/releases/tag/8.5.10
GHSA-qx2v-qp2m-jg93 https://github.com/advisories/GHSA-qx2v-qp2m-jg93
GHSA-qx2v-qp2m-jg93 https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-41305.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

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required

unchanged

changed

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/postcss/postcss
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

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none

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required

unchanged

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/postcss/postcss/releases/tag/8.5.10
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

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Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-24T16:22:58Z/ Found at https://github.com/postcss/postcss/releases/tag/8.5.10
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
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

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none

high

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none

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Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-24T16:22:58Z/ Found at https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2026-41305
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
Exploit Prediction Scoring System (EPSS)
Percentile 0.01485
EPSS Score 0.00011
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:51:18.631229+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/41xxx/CVE-2026-41305.json 38.6.0