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Details of issue NIXPKGS-2026-1258

NIXPKGS-2026-1258
published 1 month, 4 weeks ago
Permalink CVE-2026-41305
6.1 MEDIUM
  • CVSS version (CVSS): 3.1
  • Attack Vector (AV): Network (N)
  • Attack Complexity (AC): Low (L)
  • Privileges Required (PR): None (N)
  • User Interaction (UI): Required (R)
  • Scope (S): Changed (C)
  • Confidentiality (C): Low (L)
  • Integrity (I): Low (L)
  • Availability (A): None (N)
  • Modified Attack Vector (MAV): Network (N)
  • Modified Attack Complexity (MAC): Low (L)
  • Modified Privileges Required (MPR): None (N)
  • Modified User Interaction (MUI): Required (R)
  • Modified Confidentiality (MC): Low (L)
  • Modified Scope (MS): Changed (C)
  • Modified Integrity (MI): Low (L)
  • Modified Availability (MA): None (N)
updated 1 month, 4 weeks ago by @LeSuisse Activity log
  • Created suggestion
  • @LeSuisse ignored
    2 packages
    • nodePackages.postcss
    • nodePackages_latest.postcss
  • @LeSuisse restored
    2 packages
    • nodePackages.postcss
    • nodePackages_latest.postcss
  • @LeSuisse accepted
  • @LeSuisse published on GitHub
PostCSS has XSS via Unescaped </style> in its CSS Stringify Output

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.

Affected products

postcss
  • ==< 8.5.10

Matching in nixpkgs

pkgs.postcss

Transforming styles with JS plugins