{"id":"CVE-2026-77281","state":"PUBLISHED","title":"Caddy: rewrite placeholder re-expansion","description":"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.","publishedAt":"2026-09-17T21:04:58.400Z","updatedAt":"2026-09-18T14:43:34.818Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["caddyserver caddy"],"affected":[{"vendor":"caddyserver","product":"caddy","versions":[{"version":"< 2.11.4","status":"affected"}]}],"references":["https://github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9","https://github.com/caddyserver/caddy/pull/7761","https://github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e404bb","https://github.com/caddyserver/caddy/releases/tag/v2.11.4"],"weaknesses":["CWE-94","CWE-178","CWE-770"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/77xxx/CVE-2026-77281.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-77281","state":"PUBLISHED","datePublished":"2026-09-17T21:04:58.400Z","dateUpdated":"2026-09-18T14:43:34.818Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-20T19:14:21.331Z"},"containers":{"cna":{"title":"Caddy: rewrite placeholder re-expansion","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"caddyserver","product":"caddy","versions":[{"version":"< 2.11.4","status":"affected"}]}],"references":[{"url":"https://github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9","name":"https://github.com/caddyserver/caddy/security/advisories/GHSA-j8px-rmrx-76h9","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/caddyserver/caddy/pull/7761","name":"https://github.com/caddyserver/caddy/pull/7761","tags":["x_refsource_MISC"]},{"url":"https://github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e404bb","name":"https://github.com/caddyserver/caddy/commit/176b043b0104cee3f894023cd5a598ac29e404bb","tags":["x_refsource_MISC"]},{"url":"https://github.com/caddyserver/caddy/releases/tag/v2.11.4","name":"https://github.com/caddyserver/caddy/releases/tag/v2.11.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-94","lang":"en","description":"CWE-94: Improper Control of Generation of Code ('Code Injection')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-178","lang":"en","description":"CWE-178: Improper Handling of Case Sensitivity","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-17T21:04:58.400Z"},"source":{"advisory":"GHSA-j8px-rmrx-76h9","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-18T14:39:55.254322Z","id":"CVE-2026-77281","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-18T14:43:34.818Z"}}]}}}