CVE 9.8 CRITICAL

libceph: Fix potential out-of-bounds access in crush_decode()_CVE-2026-52955

June 28, 2026 invoker category_cve

9.8 / 10

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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().

AI Analysis

Out-of-bounds access in crush_decode() function in libceph

Basic Information

ID CVE-2026-52955

Source Linux

Published Jun 24, 2026 at 16:28

Modified Jun 28, 2026 at 06:37

Affected Product

Vendor Linux

Product Linux

Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2

Affected Versions Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 0
Linux Linux 0
Linux Linux 0
Linux Linux 0
Linux Linux 0
Linux Linux 0
Linux Linux 0

AI Assessment

AI Score 9.8 / 10

AI Severity Critical

Vendor Linux

Product Linux Kernel

Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2

References

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    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in crush_decode()\n\nA message of type CEPH_MSG_OSD_MAP containing a crush map with at least\none bucket has two fields holding the bucket algorithm. If the values\nin these two fields differ, an out-of-bounds access can occur. This is\nthe case because the first algorithm field (alg) is used to allocate\nthe correct amount of memory for a bucket of this type, while the second\nalgorithm field inside the bucket (b->alg) is used in the subsequent\nprocessing.\n\nThis patch fixes the issue by adding a check that compares alg and\nb->alg and aborts the processing in case they differ. Furthermore,\nb->alg is set to 0 in this case, because the destruction of the crush\nmap also uses this field to determine the bucket type, which can again\nresult in an out-of-bounds access when trying to free the memory pointed\nto by the fields of the bucket. To correctly free the memory allocated\nfor the bucket in such a case, the corresponding call to kfree is moved\nfrom the algorithm-specific crush_destroy_bucket functions to the\ngeneric crush_destroy_bucket().",
    "published": "2026-06-24T16:28:37.748Z",
    "modified": "2026-06-28T06:37:14.892Z",
    "type": "cve",
    "title": "libceph: Fix potential out-of-bounds access in crush_decode()",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5\nhttps://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622\nhttps://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a\nhttps://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a\nhttps://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5\nhttps://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d\nhttps://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa\nhttps://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970",
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        "version": "3.1"
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