CVE-2026-52955

Description

In 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().

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