CVE-2026-69153

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 8.5.19, if from is unset, an attacker can cause PreviousMap.loadFile() to read an unintended source-map file by supplying an absolute or directory-traversal sourceMappingURL. The resulting map’s sources and sourcesContent may then be exposed to the application. This issue is fixed in version 8.5.19.

Score

CVSS 4.0 6.3 Medium

Status

Analyzed - security-advisories@github.com

Published

2026-08-03

Last modified

2026-08-03

Weaknesses

CWE-200, CWE-22

Affected products

• Postcss (Postcss)

References

• https://github.com/postcss/postcss/commit/7beca139e70f9075c6b19700fcb00dd8033e5da8
• https://github.com/postcss/postcss/releases/tag/8.5.19
• https://github.com/postcss/postcss/security/advisories/GHSA-fxqj-rqcc-2cmp