SB20260819143 - Multiple vulnerabilities in Ceph

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Main Vulnerability Database SB20260819143

SB20260819143 - Multiple vulnerabilities in Ceph

Published: August 19, 2026

Security Bulletin ID SB20260819143
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Improper Verification of Cryptographic Signature (CVE-ID: CVE-2026-54330)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: 7.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to escalate privileges.

The vulnerability exists due to improper verification of cryptographic signatures in Ceph RGW\'s SigV4 handler when processing presigned PUT requests. A remote user can attach arbitrary unsigned x-amz-* headers to escalate privileges.

Exploitation requires a presigned PUT URL.


2) Improper Authorization (CVE-ID: CVE-2026-50152)

CWE-ID: CWE-285 - Improper Authorization

CVSSv4: 7 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to disclose sensitive information.

The vulnerability exists due to improper authorization in the Monitor subscription handler when handling a crafted MMonSubscribe message. A remote user can send a single crafted MMonSubscribe message to disclose sensitive information.

Exploitation requires access to the cluster and a compromised account with mon allow r caps. On cephadm-managed clusters, exposed data may include the SSH private key used by cephadm to reach hosts.


3) Improper Verification of Cryptographic Signature (CVE-ID: CVE-2026-39944)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: 7.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to escalate privileges to full RGW administrative access.

The vulnerability exists due to improper verification of a cryptographic signature in RGW STS session tokens when processing a valid STS token. A remote user can tamper with a token using CBC bit-flipping to escalate privileges to full RGW administrative access.

Exploitation requires STS to be enabled and a single valid STS token already held by the attacker.


Remediation

Install update from vendor's website.

References