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)
EPSS: 0.005 (38.3th percentile) — read the EPSS interpretation.
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.
Affected products
- Postcss — versions < 8.5.19
Weakness classification (CWE)
References
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, 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.