CVE-2026-54330
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
Ceph versions prior to 20.2.4 and 19.2.6, in the RGW SigV4 handler, do not reject requests carrying x-amz-* headers absent from the signed header set. This allows anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW honors, potentially leading to privilege escalation.
Risk Assessment
An attacker can exploit a presigned URL to gain more capabilities than intended by the signer, potentially leading to unauthorized data access and privilege escalation in the Ceph cluster.
Recommendation
Upgrade Ceph to version 20.2.4 or 19.2.6. Invalidate existing presigned URLs and educate users on secure URL generation.
Other vulnerabilities in Ceph
See all- CVE-2026-50152Critical
Ceph before versions 20.2.4 and 19.2.6 has a flaw in the Monitor subscription handler that allows a user with only read-only capabilities (mon allow r) to read the entire configuration-key store. This store contains sensitive secrets, including LUKS disk-encryption passphrases and the cephadm SSH private key.
- CVE-2026-39944High
Ceph versions prior to 20.2.4 and 19.2.6, in RADOS Gateway (RGW), protect STS session tokens with AES-128-CBC without message authentication, allowing an attacker holding a valid STS token to tamper with it undetected and escalate to full RGW administrative access.
- CVE-2025-30156High
Ceph versions prior to 20.2.4 and 19.2.6 use the CephX authentication protocol with AES-128-CBC in an unauthenticated mode, using a hard-coded initialization vector and no message authentication. An attacker with a low-privilege key can forge tickets and gain cluster-wide access, including to privileged components such as Manager, MDS, and OSD.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS