{"id":"CVE-2026-40280","state":"PUBLISHED","title":"Gotenberg SSRF via case-insensitive URL scheme bypass in webhook and downloadFrom deny-lists","description":"Gotenberg is an API-based document conversion tool. In versions 8.30.1 and earlier, the default private-IP deny-lists for the --webhook-deny-list and --api-download-from-deny-list flags use a case-sensitive regular expression (^https?://) to match URL schemes. Because Go's net/url.Parse() normalizes the scheme to lowercase before establishing the outbound TCP connection, an attacker can bypass the deny-list by simply capitalizing part of the URL scheme (e.g., HTTP://, HTTPS://, or Http://). This allows unauthenticated requests to reach internal network services, including private IP ranges, loopback addresses, and cloud instance metadata endpoints such as HTTP://169.254.169.254/latest/meta-data/. \n\nThis bypasses the same security control that was patched in CVE-2026-27018.\n\nThis issue has been fixed in version 8.31.0.","publishedAt":"2026-05-05T19:52:40.327Z","updatedAt":"2026-05-06T18:41:51.071Z","severity":{"score":7.8,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["gotenberg gotenberg"],"affected":[{"vendor":"gotenberg","product":"gotenberg","versions":[{"version":"<= 8.30.1","status":"affected"}]}],"references":["https://github.com/gotenberg/gotenberg/security/advisories/GHSA-5q7p-7jgv-ww56","https://github.com/gotenberg/gotenberg/commit/3f01ca18d3cc21375a1e2da4b5a3f261c8548e47","https://github.com/advisories/GHSA-jjwv-57xh-xr6r"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/40xxx/CVE-2026-40280.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40280","state":"PUBLISHED","datePublished":"2026-05-05T19:52:40.327Z","dateUpdated":"2026-05-06T18:41:51.071Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-10T20:22:44.034Z"},"containers":{"cna":{"title":"Gotenberg SSRF via case-insensitive URL scheme bypass in webhook and downloadFrom deny-lists","descriptions":[{"lang":"en","value":"Gotenberg is an API-based document conversion tool. In versions 8.30.1 and earlier, the default private-IP deny-lists for the --webhook-deny-list and --api-download-from-deny-list flags use a case-sensitive regular expression (^https?://) to match URL schemes. Because Go's net/url.Parse() normalizes the scheme to lowercase before establishing the outbound TCP connection, an attacker can bypass the deny-list by simply capitalizing part of the URL scheme (e.g., HTTP://, HTTPS://, or Http://). This allows unauthenticated requests to reach internal network services, including private IP ranges, loopback addresses, and cloud instance metadata endpoints such as HTTP://169.254.169.254/latest/meta-data/. \n\nThis bypasses the same security control that was patched in CVE-2026-27018.\n\nThis issue has been fixed in version 8.31.0."}],"affected":[{"vendor":"gotenberg","product":"gotenberg","versions":[{"version":"<= 8.30.1","status":"affected"}]}],"references":[{"url":"https://github.com/gotenberg/gotenberg/security/advisories/GHSA-5q7p-7jgv-ww56","name":"https://github.com/gotenberg/gotenberg/security/advisories/GHSA-5q7p-7jgv-ww56","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/gotenberg/gotenberg/commit/3f01ca18d3cc21375a1e2da4b5a3f261c8548e47","name":"https://github.com/gotenberg/gotenberg/commit/3f01ca18d3cc21375a1e2da4b5a3f261c8548e47","tags":["x_refsource_MISC"]},{"url":"https://github.com/advisories/GHSA-jjwv-57xh-xr6r","name":"https://github.com/advisories/GHSA-jjwv-57xh-xr6r","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-05T19:52:40.327Z"},"source":{"advisory":"GHSA-5q7p-7jgv-ww56","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/gotenberg/gotenberg/security/advisories/GHSA-5q7p-7jgv-ww56","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-06T18:41:39.882866Z","id":"CVE-2026-40280","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-06T18:41:51.071Z"}}]}}}