Main Vulnerability Database Vulnerabilities #VU139097

Path traversal in Postcss - CVE-2026-45623

Published: July 22, 2026

Vulnerability identifier: #VU139097

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-45623

CWE-ID: CWE-22

Exploitation vector: Remote access

Exploit availability: Public exploit is available

Vulnerability details

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in lib/previous-map.js. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Affected software

Postcss
Crowd Data Center
Confluence Data Center
Bamboo Data Center

How to mitigate CVE-2026-45623

Install updates from vendor's website.

Postcss - update to 8.5.12
Crowd Data Center - update to 7.2.2
Confluence Data Center - addressed in versions 9.2.22, 10.2.15
Bamboo Data Center - addressed in versions 10.2.21, 12.1.9

Links to Public Exploits and PoC-codes

Exploit #12836 - Arbitrary file read and information disclosure via attacker-controlled sourceMappingURL in CSS comments (July 22, 2026)

External References

https://github.com/postcss/postcss/security/advisories/GHSA-6g55-p6wh-862q