CVE-2026-54330: Ceph

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

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 products

• Ceph Ceph: from 19.0.0, before 19.2.6 (fixed in 19.2.6); from 20.0.0, before 20.2.4 (fixed in 20.2.4)

Published 2026-08-28. Last modified 2026-09-08.