libceph: reject buckets with mismatched CRUSH ids
Published Sep 11, 2026
9.8
CRITICALCVSS 3.1
EPSS 0.76%
Description
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.
Affected products
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- Version StatusaffectedConstraints
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- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
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- Version
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- Version 4.11StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<4.11
- Version 5.10.270StatusunaffectedConstraints<=5.10.*
- Version 5.15.221StatusunaffectedConstraints<=5.15.*
- Version 6.1.188StatusunaffectedConstraints<=6.1.*
- Version 6.12.109StatusunaffectedConstraints<=6.12.*
- Version 6.18.50StatusunaffectedConstraints<=6.18.*
- Version 6.6.157StatusunaffectedConstraints<=6.6.*
- Version 7.2.4StatusunaffectedConstraints<=7.2.*
- Version 7.3-rc1StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
Red Hat Enterprise Linux 10
kernel
Affected
Red Hat Enterprise Linux 10
kernel-rt
Affected
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Affected
Red Hat Enterprise Linux 7
kernel-rt
Affected
Red Hat Enterprise Linux 8
kernel
Affected
Red Hat Enterprise Linux 8
kernel-rt
Affected
Red Hat Enterprise Linux 9
kernel
Affected
Red Hat Enterprise Linux 9
kernel-rt
Affected
Red Hat OpenShift Container Platform 4
openshift/ose-rhel-coreos-8
Affected
Red Hat OpenShift Container Platform 4
openshift/ose-rhel-coreos-9
Affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 10 | kernel-rt | Affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | n/a |
| Red Hat Enterprise Linux 9 | kernel | Affected | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | n/a |
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Affected | n/a |
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
1 other source (Red Hat) ▾
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Sep–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.76% (0.00755) | 53.53th | v5 (v2026.06.15) |
| Sep 12, 2026 | 0.17% (0.00168) | 6.34th | v5 (v2026.06.15) |
References (13)
- https://access.redhat.com/security/cve/CVE-2026-89656 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2532365 Issue Tracking
- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89656.mbox
- https://git.kernel.org/stable/c/00562ccd4e88d092b9b851df50fad20442bfeb24
- https://git.kernel.org/stable/c/3516a4131c4e45d62ee4e42e82c36930e8c1fbbd
- https://git.kernel.org/stable/c/3cde4a8302301679937474a5f7a851394cc1bd11
- https://git.kernel.org/stable/c/4aeb93daadf388e72073abc204312dd364eeb30a
- https://git.kernel.org/stable/c/6e5c6ce252b1eccfd41670a5cf95ab44f7ba7022
- https://git.kernel.org/stable/c/79900d978158b2d80eef952fc41b9e4dc58d7b83
- https://git.kernel.org/stable/c/baad5875fdd2f5e248250fc3519bb045d64f1716
- https://git.kernel.org/stable/c/ee59040d6ed1a5f8d10d27174b8f32c90ca8e89a
- https://nvd.nist.gov/vuln/detail/CVE-2026-89656
- https://www.cve.org/CVERecord?id=CVE-2026-89656
Change history (0)
No recorded changes yet.