Path Traversal in Postcss
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (39.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Postcss — versions < 8.5.19
Weakness classification (CWE)
References
- github.com/postcss/postcss/commit/7beca139e70f9075c6b19700fcb00dd8033e5da8 (Patch)
- github.com/postcss/postcss/releases/tag/8.5.19 (Product, Release Notes)
- github.com/postcss/postcss/security/advisories/GHSA-fxqj-rqcc-2cmp (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-69153?
- CVE-2026-69153 is a medium-severity vulnerability in Postcss, classified under Path Traversal. CVSS score: 5.3/10. Published 2026-08-03.
- How severe is CVE-2026-69153?
- Medium severity. CVSS v3 base score is 5.3 out of 10.