js-yaml is a JavaScript YAML parser and dumper.
CVE-2025-64718
js-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (proto). All users who parse untrusted yaml documents may be impacted. The problem is patched in js-yaml 4.1.1 and 3.14.2. Users can protect against this kind of attack on the server by using node --disable-proto=delete or deno (in Deno, pollution protection is on by default).
Assessment
- CVSS
- 5.3 (v3.1)
- Severity
- Medium
- EPSS
- 0.42% 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
- 13 November 2025
- Last updated
- 7 October 2026
- Weakness
- CWE-1321
- Assigner
- security-advisories@github.com
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
At the source
References
- https://github.com/nodeca/js-yaml/commit/383665ff4248ec2192d1274e934462bb30426879
- https://github.com/nodeca/js-yaml/commit/5278870a17454fe8621dbd8c445c412529525266
- https://github.com/nodeca/js-yaml/issues/730#issuecomment-3549635876
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-mh29-5h37-fv8m
- https://github.com/advisories/GHSA-mh29-5h37-fv8m
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