| Name | CVE-2026-84375 |
| Description | 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1146637 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| node-js-yaml (PTS) | bookworm, trixie | 4.1.0+dfsg+~4.0.5-7 | vulnerable |
| forky, sid | 4.3.2+~4.0.9-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| node-js-yaml | source | (unstable) | 4.3.2+~4.0.9-1 | 1146637 |
[trixie] - node-js-yaml <no-dsa> (Minor issue)
[bookworm] - node-js-yaml <postponed> (Minor issue)
https://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh
https://github.com/nodeca/js-yaml/pull/797
Fixed by: https://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b (4.3.2)
Fixed by: https://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639 (3.15.2)