CVE-2026-84375
highjs-yaml is a JavaScript YAML parser and dumper.
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. In v3 & v4, merge is enabled by default so the severity score is higher. This issue is fixed in versions 3.15.2, 4.3.2, and 5.4.1.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639 security-advisories@github.com
- https://github.com/nodeca/js-yaml/commit/6a8e05f9a485188ed730ac81e81ae221352ef480 security-advisories@github.com
- https://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b security-advisories@github.com
- https://github.com/nodeca/js-yaml/pull/797 security-advisories@github.com
- https://github.com/nodeca/js-yaml/releases/tag/3.15.2 security-advisories@github.com
- https://github.com/nodeca/js-yaml/releases/tag/4.3.2 security-advisories@github.com
- https://github.com/nodeca/js-yaml/releases/tag/5.4.1 security-advisories@github.com
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh security-advisories@github.com