Description
A flaw was found in Ceph RGW's SigV4 signature verification handler. When processing S3 requests, RGW verifies only the headers explicitly listed in the X-Amz-SignedHeaders field but does not reject requests that carry additional unsigned x-amz-* headers. This diverges from the AWS S3 specification, which requires all x-amz-* headers to be signed. As a result, anyone holding a presigned PUT URL can attach arbitrary unsigned x-amz-* headers that RGW will honor, effectively escalating their privileges beyond what the original URL signer authorized. This can lead to unauthorized access to and modification of S3 objects.
Published: n/a
Score: 8.2 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Thu, 20 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in Ceph RGW's SigV4 signature verification handler. When processing S3 requests, RGW verifies only the headers explicitly listed in the X-Amz-SignedHeaders field but does not reject requests that carry additional unsigned x-amz-* headers. This diverges from the AWS S3 specification, which requires all x-amz-* headers to be signed. As a result, anyone holding a presigned PUT URL can attach arbitrary unsigned x-amz-* headers that RGW will honor, effectively escalating their privileges beyond what the original URL signer authorized. This can lead to unauthorized access to and modification of S3 objects.
Title ceph: ceph: RGW SigV4 verifier allows attachment of arbitrary unsigned x-amz-* headers leading to privilege escalation
Weaknesses CWE-347
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N'}

threat_severity

Important


Subscriptions

No data.

cve-icon MITRE

No data.

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-19T17:57:46Z

Links: CVE-2026-54330 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses