CVE-2026-52955: Linux kernel · libceph: Fix potential out-of-bounds access in crush_decode()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in fb176a99e4c1a5a8448a83d83d3606203ba81faa : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in fb176a99e4c1a5a8448a83d83d3606203ba81faa, ebe76d58a48a48031b98543d86c4cd30a825b622, ea0d42137f0c06da71e37ffc647aab4c5309599a +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5 (opens in a new tab)
- git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622 (opens in a new tab)
- git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a (opens in a new tab)
- git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a (opens in a new tab)
- git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5 (opens in a new tab)
- git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d (opens in a new tab)
- git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa (opens in a new tab)
- git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-52955 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2492328 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52955.json (opens in a new tab)