ceph: Use of a Broken or Risky Cryptographic Algorithm
CVE-2025-30156 is a high-severity use of a broken or risky cryptographic algorithm vulnerability in ceph, with a CVSS 3.1 base score of 8.9 out of 10. It can be exploited from the same local network by an attacker with a low-privileged account, without any action from a user. Affected ceph versions: < 19.2.6; >= 20.0.0, < 20.2.4. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.09% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of ceph you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L. Scored by CNA (github.com).
Official description
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 CephX authentication protocol encrypts tickets with AES-128-CBC in an unauthenticated mode that uses a hard-coded initialization vector and no message authentication, allowing an attacker to forge credentials and gain cluster-wide access. Because the ciphertext is malleable and the monitor will encrypt attacker-chosen entity names, an attacker holding one low-privilege key and able to observe CephX traffic can use the monitor as an encryption oracle and splice ciphertext blocks into valid tickets for privileged entities such as Manager, MDS, and OSD. The same lack of authentication also lets an attacker with CephX permissions escalate privileges by flipping a single bit in a service ticket to set its allow_all field to true. This issue is fixed in versions 20.2.4 and 19.2.6.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of a Broken or Risky Cryptographic Algorithm
The product uses a broken or risky cryptographic algorithm or protocol.
How developers prevent this class of flaw
- Ensure that the design allows one cryptographic algorithm to be replaced with another in the next generation or version. Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms. With hardware, design the product at the Intellectual Property (IP) level so that one cryptographic algorithm can be replaced with another in the next generation of the hardware product.
- Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Industry-standard implementations will save development time and may be more likely to avoid errors that can occur during implementation of cryptographic algorithms. Consider the ESAPI Encryption feature.
More Use of a Broken or Risky Cryptographic Algorithm vulnerabilities (CWE-327)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Our coverage
Other vulnerabilities in ceph
- 8.1 High severity
- 9.1 Critical severity
- 8.8 High severity
- 7.5 High severity
- 8.1 High severity
- 7.8 High severity
Recent Use of a Broken or Risky Cryptographic Algorithm vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
- 8.7 High severity
- 7.5 High severity
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