{"id":"CVE-2026-71303","state":"PUBLISHED","title":"Lemur: Incomplete fix for CVE-2026-55166 -- ACME authority update endpoint allows non-admin to replace `acme_url` with internal IP, bypassing allowlist","description":"Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the stored acme_url with an internal service or instance-metadata URL such as 169.254.169.254. The next issuance operation loaded that value and passed it to ClientV2.get_directory, causing an outbound request from the Lemur backend. This bypassed the creation-time mitigation for CVE-2026-55166 and could expose internal services or cloud metadata. The fix revalidates acme_url whenever authority options are updated. This issue is fixed in version 1.9.3.","publishedAt":"2026-08-18T19:03:55.524Z","updatedAt":"2026-08-18T19:46:07.340Z","severity":{"score":7.7,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["Netflix lemur"],"affected":[{"vendor":"Netflix","product":"lemur","versions":[{"version":"< 1.9.3","status":"affected"}]}],"references":["https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr","https://github.com/Netflix/lemur/commit/edca0390f930344d65ff4ca37a669c2320e3dfad","https://github.com/Netflix/lemur/releases/tag/v1.9.3"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/71xxx/CVE-2026-71303.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-71303","state":"PUBLISHED","datePublished":"2026-08-18T19:03:55.524Z","dateUpdated":"2026-08-18T19:46:07.340Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-05T18:14:42.063Z"},"containers":{"cna":{"title":"Lemur: Incomplete fix for CVE-2026-55166 -- ACME authority update endpoint allows non-admin to replace `acme_url` with internal IP, bypassing allowlist","descriptions":[{"lang":"en","value":"Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the stored acme_url with an internal service or instance-metadata URL such as 169.254.169.254. The next issuance operation loaded that value and passed it to ClientV2.get_directory, causing an outbound request from the Lemur backend. This bypassed the creation-time mitigation for CVE-2026-55166 and could expose internal services or cloud metadata. The fix revalidates acme_url whenever authority options are updated. This issue is fixed in version 1.9.3."}],"affected":[{"vendor":"Netflix","product":"lemur","versions":[{"version":"< 1.9.3","status":"affected"}]}],"references":[{"url":"https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr","name":"https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/Netflix/lemur/commit/edca0390f930344d65ff4ca37a669c2320e3dfad","name":"https://github.com/Netflix/lemur/commit/edca0390f930344d65ff4ca37a669c2320e3dfad","tags":["x_refsource_MISC"]},{"url":"https://github.com/Netflix/lemur/releases/tag/v1.9.3","name":"https://github.com/Netflix/lemur/releases/tag/v1.9.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.7,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","version":"3.1"}}],"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":"2026-08-18T19:03:55.524Z"},"source":{"advisory":"GHSA-v5rc-cpwc-cfpr","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-18T19:45:59.586663Z","id":"CVE-2026-71303","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-18T19:46:07.340Z"}}]}}}