{"id":"UBUNTU-CVE-2026-4926","details":"Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.","modified":"2026-05-21T12:15:06.655826384Z","published":"2026-03-26T19:17:00Z","withdrawn":"2026-05-21T12:08:04Z","upstream":["CVE-2026-4926"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-4926"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-4926"},{"type":"REPORT","url":"https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-j3q9-mxjg-w52f"},{"type":"REPORT","url":"https://cna.openjsf.org/security-advisories.html"}],"affected":[{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"1.0.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"1.0.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.0.0-2","3.1.0-1","6.1.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"6.1.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.2.0-1","6.2.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"6.2.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.2.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"6.2.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.3.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"6.3.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.json"}},{"package":{"name":"node-path-to-regexp","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/node-path-to-regexp?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.3.0-1","8.3.0-1","8.4.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-path-to-regexp","binary_version":"8.4.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4926.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:H"},{"type":"Ubuntu","score":"medium"}]}