nfsd: clear opcnt on compound arg release to prevent OOB read
Summary
| CVE | CVE-2026-89691 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-11 20:19:56 UTC |
| Updated | 2026-09-13 07:17:34 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: nfsd: clear opcnt on compound arg release to prevent OOB read nfsd4_release_compoundargs() resets args->ops to the inline iops[8] array when the dynamically-allocated ops buffer is freed, but leaves args->opcnt at its original value (which can be up to 200 for NFSv4.1+ compounds). If rq_status_counter is stuck at an odd value (which can happen when nfsd_dispatch() hits an error path after setting it odd), the RPC status dumpit handler reads min(opcnt, 16) entries from args->ops[]. Since iops only has 8 elements and is the last field in struct nfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory and leaks it to userspace via netlink. Zero opcnt unconditionally in nfsd4_release_compoundargs() so stale compound metadata is never exposed through the status interface. [ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ] |
Risk And Classification
Primary CVSS: v3.1 7.1 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
EPSS: 0.001250000 probability, percentile 0.025060000 (date 2026-09-13)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.1 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H |
| 3.1 | CNA | DECLARED | 7.1 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected bd9d6a3efa9709e653aafbeb859289feccb8e70c 58bcdfb2b2e412088839ae740b1a95154dc0b8d0 git | Not specified |
| CNA | Linux | Linux | affected bd9d6a3efa9709e653aafbeb859289feccb8e70c e879148867bd4c4cac42e063ffaffa187dddc6fe git | Not specified |
| CNA | Linux | Linux | affected bd9d6a3efa9709e653aafbeb859289feccb8e70c c1a4f7b1848f95302df598217e1c7a1410c2d0c5 git | Not specified |
| CNA | Linux | Linux | affected bd9d6a3efa9709e653aafbeb859289feccb8e70c ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a git | Not specified |
| CNA | Linux | Linux | affected 6.7 | Not specified |
| CNA | Linux | Linux | unaffected 6.7 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.109 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.50 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.4 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.