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CVE-2026-52955

Full vulnerability record from the local CVENow database.

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().

Severity
CRITICAL
CVSS score
9.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-24 17:17:05.670000
Last modified
2026-10-19 20:18:50.527000
View original CVE JSON 
{
  "id": "CVE-2026-52955",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-24T17:17:05.670",
  "lastModified": "2026-10-19T20:18:50.527",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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()."
    }
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