CVE-2026-89656libceph: reject buckets with mismatched CRUSH ids
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: libceph: reject buckets with mismatched CRUSH ids crush_decode() stores bucket data by array slot, and the mapper later derives the per-bucket workspace index from the decoded bucket id. A malformed map can therefore make one bucket reuse another bucket's workspace by encoding an id different from -1 - slot. For uniform buckets, the second replica selection expands the source bucket's permutation into that aliased workspace buffer. If the source bucket is larger than the aliased bucket, the write runs past the smaller permutation array and can escape the kvmalloc'd CRUSH workspace. KASAN reports a slab OOB write of 4 bytes in bucket_perm_choose(). Reject buckets whose encoded id does not match their array slot. Valid CRUSH maps already use the canonical negative id corresponding to the bucket slot, so this restores the invariant expected by work->work[-1 - in->id] without changing valid map behavior.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 66a0e2d579dbec5c676cfe446234ffebb267c564 before ee59040d6ed1a5f8d10d27174b8f32c90ca8e89a; from 66a0e2d579dbec5c676cfe446234ffebb267c564 before baad5875fdd2f5e248250fc3519bb045d64f1716; 66a0e2d579dbec5c676cfe446234ffebb267c564 builds before 4aeb93daadf388e72073abc204312dd364eeb30a; 66a0e2d579dbec5c676cfe446234ffebb267c564 builds before 6e5c6ce252b1eccfd41670a5cf95ab44f7ba7022; from 66a0e2d579dbec5c676cfe446234ffebb267c564 before 3516a4131c4e45d62ee4e42e82c36930e8c1fbbd; from 66a0e2d579dbec5c676cfe446234ffebb267c564 before 00562ccd4e88d092b9b851df50fad20442bfeb24; from 66a0e2d579dbec5c676cfe446234ffebb267c564 before 79900d978158b2d80eef952fc41b9e4dc58d7b83; 66a0e2d579dbec5c676cfe446234ffebb267c564 builds before 3cde4a8302301679937474a5f7a851394cc1bd11 | CNA record |
References
- https://git.kernel.org/stable/c/ee59040d6ed1a5f8d10d27174b8f32c90ca8e89a
- https://git.kernel.org/stable/c/baad5875fdd2f5e248250fc3519bb045d64f1716
- https://git.kernel.org/stable/c/4aeb93daadf388e72073abc204312dd364eeb30a
- https://git.kernel.org/stable/c/6e5c6ce252b1eccfd41670a5cf95ab44f7ba7022
- https://git.kernel.org/stable/c/3516a4131c4e45d62ee4e42e82c36930e8c1fbbd
- https://git.kernel.org/stable/c/00562ccd4e88d092b9b851df50fad20442bfeb24
- https://git.kernel.org/stable/c/79900d978158b2d80eef952fc41b9e4dc58d7b83
- https://git.kernel.org/stable/c/3cde4a8302301679937474a5f7a851394cc1bd11
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.