{"id":"UBUNTU-CVE-2026-77281","details":"Caddy is an extensible server platform that uses TLS by default. In version 2.11.3 and earlier, three configuration-dependent weaknesses affect the handler and placeholder layer. In modules/caddyhttp/rewrite/rewrite.go, Rewrite.Rewrite() can pass attacker-controlled replacement bytes through buildQueryString for a second placeholder expansion when a rewrite URI ends with a literal question mark, allowing injected environment or request-variable placeholders to disclose data and, when the file provider is registered, allowing injected file placeholders to disclose readable files. The  issue is fixed in version 2.11.4.","modified":"2026-09-23T23:35:44Z","published":"2026-09-17T21:17:00Z","upstream":["CVE-2026-77281"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-77281"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-77281"},{"type":"REPORT","url":"https://github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9"},{"type":"REPORT","url":"https://github.com/caddyserver/caddy/pull/7761"},{"type":"REPORT","url":"https://github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e404bb"},{"type":"REPORT","url":"https://github.com/caddyserver/caddy/releases/tag/v2.11.4"}],"affected":[{"package":{"name":"caddy","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/caddy?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.2-6","2.6.2-6ubuntu0.24.04.1","2.6.2-6ubuntu0.24.04.2","2.6.2-6ubuntu0.24.04.2+esm1","2.6.2-6ubuntu0.24.04.3","2.6.2-6ubuntu0.24.04.3+esm1","2.6.2-6ubuntu0.24.04.3+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"2.6.2-6ubuntu0.24.04.3+esm2","binary_name":"caddy"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77281.json"}},{"package":{"name":"caddy","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/caddy?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.2-12","2.6.2-14","2.6.2-14ubuntu0.26.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"caddy","binary_version":"2.6.2-14ubuntu0.26.04.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77281.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}