CVE-2026-73646

EUVD-2026-60239

17.08.2026, 16:17

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18.

Path Traversal

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
GitHub_M	CNA	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: 42.69%

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
postcss	postcss	𝑥 < 8.5.18	CNA

Debian Releases

Debian Product

Codename

node-postcss

bookworm	postponed
forky	8.5.28+~cs10.2.24-1 fixed
sid	8.5.28+~cs10.2.24-1 fixed
trixie	no-dsa

Ubuntu Releases

Ubuntu Product

Codename

node-postcss

focal	needs-triage
jammy	needs-triage
noble	needs-triage
resolute	needs-triage

Common Weakness Enumeration

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

References

https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c

https://github.com/postcss/postcss/releases/tag/8.5.18

https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849