Detections
Analytics
CVE-2026-84375
high
Description
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, 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. This issue is fixed in versions 3.15.2 and 4.3.2.
References
https://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh
https://github.com/nodeca/js-yaml/releases/tag/4.3.2
https://github.com/nodeca/js-yaml/releases/tag/3.15.2
https://github.com/nodeca/js-yaml/pull/797
https://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b
https://github.com/nodeca/js-yaml/commit/6a8e05f9a485188ed730ac81e81ae221352ef480
https://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639