{"id":"UBUNTU-CVE-2026-53550","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.","modified":"2026-07-01T23:40:10.428828553Z","published":"2026-06-22T16:16:00Z","upstream":["CVE-2026-53550"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53550"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53550"}],"affected":[{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.9.1+dfsg-1","3.10.0+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"3.10.0+dfsg-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53550.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.13.1+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"3.13.1+dfsg-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53550.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.14.1+dfsg+~3.12.6-2","4.1.0+dfsg+~4.0.5-4ubuntu1","4.1.0+dfsg+~4.0.5-5","4.1.0+dfsg+~4.0.5-6"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"4.1.0+dfsg+~4.0.5-6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53550.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg+~4.0.5-7"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"4.1.0+dfsg+~4.0.5-7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53550.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg+~4.0.5-7"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"4.1.0+dfsg+~4.0.5-7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53550.json"}},{"package":{"name":"node-js-yaml","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/node-js-yaml?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg+~4.0.5-7","4.1.1+dfsg+~4.0.9-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-js-yaml","binary_version":"4.1.1+dfsg+~4.0.9-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}