{"id":"CVE-2026-54330","summary":"Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation","details":"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.","aliases":["BIT-ceph-2026-54330","GHSA-rmjq-ffrm-j6vj"],"modified":"2026-10-28T02:30:29.615387435Z","published":"2026-08-27T20:59:24.688Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54330.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54330.json"},{"type":"ADVISORY","url":"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54330"},{"type":"FIX","url":"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7"},{"type":"FIX","url":"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ceph/ceph","events":[{"introduced":"1680e466aab77cdf9ba07394bea664106580b32b"},{"fixed":"f9fd95b4335bad6a26d7a74468f55d269e8dbef4"},{"introduced":"3d911bce7d6557aa2d1826543a4a4e88981639da"},{"fixed":"7f793731f1b39eb4f465e960113d2363c311b964"},{"fixed":"5837aa8e60471128dbb672b0ff6f1b1feebe08a7"},{"fixed":"5978c866d4a0812fbb024745c4f1e79aaecd6c6a"}],"database_specific":{"extracted_events":[{"strategy":"StringRangeExpression","range":[{"introduced":"19.0.0"},{"fixed":"19.2.6"}],"source":"AFFECTED_FIELD"},{"strategy":"StringRangeExpression","range":[{"introduced":"20.0.0"},{"fixed":"20.2.4"}],"source":"AFFECTED_FIELD"},{"range":[{"fixed":"5837aa8e60471128dbb672b0ff6f1b1feebe08a7"}],"source":"REFERENCES_COMMIT"},{"range":[{"fixed":"5978c866d4a0812fbb024745c4f1e79aaecd6c6a"}],"source":"REFERENCES_COMMIT"}]}}],"versions":["v20.2.3","v19.2.5","v20.2.2-pre.ibm","v20.2.1-pre.ibm.0","v20.1.0-pre.ibm.2","v20.1.0-pre.ibm.1","v20.0.0-pre.ibm","v19.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54330.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}