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CVE-2026-52955

CRITICAL 9.8

Published 2026-06-24 · Last modified 2026-07-15

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().

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 31st percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

9.8CVSS 3.1 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-52955/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-52955/poc.json

Affected

Vendors Linux Red Hat

Products Linux Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Linux Kernel

Weakness (CWE)

  • CWE-131: Incorrect Calculation of Buffer Size
  • CWE-125: Out-of-bounds read

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
LinuxLinux Kernel≥ 2.6.34.1 and < 5.10.258
LinuxLinux Kernel≥ 5.11 and < 5.15.209
LinuxLinux Kernel≥ 5.16 and < 6.1.175
LinuxLinux Kernel≥ 6.2 and < 6.6.141
LinuxLinux Kernel≥ 6.7 and < 6.12.91
LinuxLinux Kernel≥ 6.13 and < 6.18.33
LinuxLinux Kernel≥ 6.19 and < 7.0.10
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel2.6.34
LinuxLinux Kernel7.1
LinuxLinux Kernel7.1
LinuxLinux Kernel7.1

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • MEDIUM 4.7 v3.1 · ADP Primary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • MEDIUM 4.7 v3.1 · NVD Secondary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Patches & mitigations

Advisories

Sources: NVD · CVE.org · EPSS