Description
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.
Affected products
postcss: postcss
References4
- github.com/postcss/postcss/security/advisories/GHSA-fxqj-rqcc-2… ExploitMitigationVendor Advisory
- github.com/postcss/postcss/security/advisories/GHSA-fxqj-rqcc-2… ExploitMitigationVendor Advisory
- github.com/postcss/postcss/commit/7beca139e70f9075c6b19700fcb00… Patch
- github.com/postcss/postcss/releases/tag/8.5.19 ProductRelease Notes
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - CVSS 4.0
-
6.3
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 40 · as of 13 November 2026
- CWE
- CWE-22CWE-200
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