{"id":"BIT-ceph-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":["CVE-2026-54330","GHSA-rmjq-ffrm-j6vj"],"modified":"2026-09-02T16:29:50.168962267Z","published":"2026-09-02T14:37:35.258Z","database_specific":{"severity":"High","cpes":["cpe:2.3:a:linuxfoundation:ceph:*:*:*:*:*:*:*:*"]},"references":[{"type":"WEB","url":"https://github.com/ceph/ceph/commit/5837aa8e60471128dbb672b0ff6f1b1feebe08a7"},{"type":"WEB","url":"https://github.com/ceph/ceph/commit/5978c866d4a0812fbb024745c4f1e79aaecd6c6a"},{"type":"WEB","url":"https://github.com/ceph/ceph/security/advisories/GHSA-rmjq-ffrm-j6vj"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54330"}],"affected":[{"package":{"name":"ceph","ecosystem":"Bitnami","purl":"pkg:bitnami/ceph"},"ranges":[{"type":"SEMVER","events":[{"introduced":"19.0.0"},{"fixed":"19.2.6"},{"introduced":"20.0.0"},{"fixed":"20.2.4"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/ceph/BIT-ceph-2026-54330.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}],"schema_version":"1.9.0"}