{"id":"CVE-2026-53550","summary":"js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases","details":"js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (\u003c\u003c) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.","aliases":["GHSA-h67p-54hq-rp68"],"modified":"2026-07-11T04:04:11.025541924Z","published":"2026-06-22T14:59:14.906Z","related":["CGA-hxp5-835r-fjv4","openSUSE-SU-2026:11148-1","openSUSE-SU-2026:11149-1","openSUSE-SU-2026:21176-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53550.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-407"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53550.json"},{"type":"ADVISORY","url":"https://github.com/nodeca/js-yaml/security/advisories/GHSA-h67p-54hq-rp68"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53550"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nodeca/js-yaml","events":[{"introduced":"0"},{"fixed":"c34b6c40027a769eb0d67958ae615268a1d55f54"},{"introduced":"ee74ce4b4800282b2f23b776be7dc95dfe34db1c"},{"fixed":"590dbabadd172b099c07654fab2eabec8c7a07b9"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.15.0"},{"introduced":"4.0.0"},{"fixed":"4.2.0"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*"}}],"versions":["3.14.2","4.1.1","3.14.1","4.1.0","4.0.0","3.14.0","3.13.1","3.13.0","3.12.2","3.12.1","3.12.0","3.11.0","3.10.0","3.9.1","3.9.0","3.8.4","3.8.3","3.8.2","3.8.1","3.8.0","3.7.0","3.6.1","3.6.0","3.5.5","3.5.4","3.5.3","3.5.2","3.5.1","3.5.0","3.4.6","3.4.5","3.4.4","3.4.3","3.4.2","3.4.1","3.4.0","3.3.1","3.3.0","3.2.7","3.2.6","3.2.5","3.2.4","3.2.3","3.2.2","3.2.1","3.2.0","3.1.0","3.0.2","3.0.1","3.0.0","2.1.3","2.1.2","2.1.1","2.1.0","2.0.5","2.0.4","2.0.3","2.0.2","2.0.1","2.0.0","1.0.3","1.0.2","1.0.1","1.0.0","0.3.7","0.3.5","0.3.4","0.3.3","0.3.2","0.2.2","0.2.1","0.2.0","0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53550.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}