CVE-2026-52955
CRITICAL 9.8In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in crush_decode() A message of type CEPH_MSG_OSD_MAP containing a crush map with at least one bucket has two fields holding the bucket algorithm. If the values in these two fields differ, an out-of-bounds access can occur. This is the case because the first algorithm field (alg) is used to allocate the correct amount of memory for a bucket of this type, while the second algorithm field inside the bucket (b->alg) is used in the subsequent processing. This patch fixes the issue by adding a check that compares alg and b->alg and aborts the processing in case they differ. Furthermore, b->alg is set to 0 in this case, because the destruction of the crush map also uses this field to determine the bucket type, which can again result in an out-of-bounds access when trying to free the memory pointed to by the fields of the bucket. To correctly free the memory allocated for the bucket in such a case, the corresponding call to kfree is moved from the algorithm-specific crush_destroy_bucket functions to the generic crush_destroy_bucket().
Severe if exploited (CVSS 9.8), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 30th percentile
Impact if exploited
9.8CVSS 3.1 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Affected
Products Linux Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 6
Weakness (CWE)
- CWE-131
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Technical & other
- https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5
- https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622
- https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a
- https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a
- https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5
- https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d
- https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa
- https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970
- https://access.redhat.com/security/cve/CVE-2026-52955
- https://bugzilla.redhat.com/show_bug.cgi?id=2492328
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json