CVE-2026-52955
In the Linux kernel, the following vulnerability has been resolved:
libceph: Fix potential out-of-bounds access in crush_decode()
A message of type CEPHMSGOSD_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 crushdestroybucket functions to the
generic crushdestroybucket().
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version
Related Resources
References
https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d, https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a, https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970, https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5, https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5, https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a, https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622, https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa, https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json, https://access.redhat.com/security/cve/CVE-2026-52955, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52955.json, https://nvd.nist.gov/vuln/detail/CVE-2026-52955, https://bugzilla.redhat.com/show_bug.cgi?id=2492328, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git