{"id":"CVE-2026-54330","state":"PUBLISHED","title":"Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation","description":"Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL's signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6.","publishedAt":"2026-08-27T20:59:24.688Z","updatedAt":"2026-09-01T03:56:17.801Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["ceph ceph"],"affected":[{"vendor":"ceph","product":"ceph","versions":[{"version":">= 19.0.0, < 19.2.6","status":"affected"},{"version":">= 20.0.0, < 20.2.4","status":"affected"}]}],"references":["https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj","https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7","https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/54xxx/CVE-2026-54330.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54330","state":"PUBLISHED","datePublished":"2026-08-27T20:59:24.688Z","dateUpdated":"2026-09-01T03:56:17.801Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-12T18:42:02.224Z"},"containers":{"cna":{"title":"Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation","descriptions":[{"lang":"en","value":"Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL's signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6."}],"affected":[{"vendor":"ceph","product":"ceph","versions":[{"version":">= 19.0.0, < 19.2.6","status":"affected"},{"version":">= 20.0.0, < 20.2.4","status":"affected"}]}],"references":[{"url":"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj","name":"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7","name":"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7","tags":["x_refsource_MISC"]},{"url":"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a","name":"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","lang":"en","description":"CWE-347: Improper Verification of Cryptographic Signature","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-27T20:59:24.688Z"},"source":{"advisory":"GHSA-rmjq-ffrm-j6vj","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-54330"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-01T03:56:17.801Z"}}]}}}