Is there a public exploit for CVE-2026-69153?

No public exploit for CVE-2026-69153 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-69153?

CVE-2026-69153 scores CVSS 6.3 (v4.0), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.45%.

What does CVE-2026-69153 affect?

CVE-2026-69153 affects postcss postcss.

6.3 Medium

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree.

CVE-2026-69153

Summary The fix for GHSA-6g55-p6wh-862q added a guard in lib/previous-map.js PreviousMap.loadFile() that restricts an attacker-controlled sourceMappingURL (from a CSS comment) to a .map extension and, for untrusted maps, rejects .. traversal and absolute paths. The traversal/absolute rejection is nested inside if (cssFile) { ... }. When PostCSS is invoked without the from option, cssFile is falsy and that branch is skipped, leaving only the .map extension check. PreviousMap is constructed by lib/input.js whenever pathAvailable && sourceMapAvailable (under Node with source-map available), independent of opts.from/opts.map (the constructor returns early only for opts.map === false). So postcss([]).process(css) on attacker CSS reaches loadFile with cssFile undefined, and an attacker /# sourceMappingURL=/abs/path/x.map / (or ../-traversing path) is read via readFileSync. When the file is valid JSON, its sources (filesystem paths) and sourcesContent (source contents) are disclosed in the generated source map. Affected code (v8.5.22 — the release carrying the GHSA-6g55 fix) js // lib/previous-map.js loadFile(path, cssFile, trusted) { if (!trusted && !this.unsafeMap) { if…

Assessment

CVSS: 6.3 (v4.0)
Severity: Medium
EPSS: 0.45% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 3 August 2026
Last updated: 5 August 2026
Affected: postcss · postcss · postcss
Weakness: CWE-200, CWE-22
Assigner: security-advisories@github.com

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

At the source

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