{"id":"DEBIAN-CVE-2026-84375","details":"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 \u003c\u003c. 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.","modified":"2026-10-30T10:00:35.114080786Z","published":"2026-09-01T22:17:19.440Z","upstream":["CVE-2026-84375"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-84375"}],"affected":[{"package":{"name":"node-js-yaml","ecosystem":"Debian:12","purl":"pkg:deb/debian/node-js-yaml?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg+~4.0.5-7","4.1.1+dfsg+~4.0.9-1","4.2.0+~4.0.9-1","4.2.0+~4.0.9-2","4.3.2+~4.0.9-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84375.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Debian:13","purl":"pkg:deb/debian/node-js-yaml?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg+~4.0.5-7","4.1.1+dfsg+~4.0.9-1","4.2.0+~4.0.9-1","4.2.0+~4.0.9-2","4.3.2+~4.0.9-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84375.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Debian:14","purl":"pkg:deb/debian/node-js-yaml?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.3.2+~4.0.9-1"}]}],"versions":["4.1.0+dfsg+~4.0.5-7","4.1.1+dfsg+~4.0.9-1","4.2.0+~4.0.9-1","4.2.0+~4.0.9-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84375.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}