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Vulnerabilities

Vulnerability · CVE-2026-41305

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree.

Published Apr 24, 2026 · catalog updated Jun 17, 2026 · PostCSS takes a CSS

Check if you run it

No confirmed exploitation is on record for CVE-2026-41305. EPSS is 0.26%. Act only if a listed version of PostCSS takes a CSS is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (PostCSS takes a CSS).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.26%
Remediation
Advisory link
Affected products
See sources for product scope

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 sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML tags, in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-41305

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-41305. EPSS is 0.26%. Act only if a listed version of PostCSS takes a CSS is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.26%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 24, 2026 · NIST NVD

    Detected

    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 sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML tags, in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML tags, in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.

Sources

  • CVE.orgVulnerability recordCVE-2026-41305

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-41305

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-41305

    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 sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for em

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.