---
id: CVE-2026-89690
title: 'nfsd: defer vfree of compound ops to fix rpc_status UAF'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nfsd: defer vfree of compound ops to fix rpc_status UAF

  The rpc_status netlink dumpit walks every in-flight svc_rqst under
  rcu_read_lock and, for NFSv4 requests, reads…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-825
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c <
    48f72aff24f7a7329209dc6cbc27c869f3e3595c
  - >-
    Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c <
    6703199f4d7e7f37d6a726a849eb358e8fae72fb
  - >-
    Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c <
    19413ccc45070a7270b9e25c2a258daf7f91de42
  - >-
    Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c <
    fca26a3fc19ed02278aa2a150af82d43db0302cb
  - Linux 6.7
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:51:03.524Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89690'
references:
  - url: 'https://git.kernel.org/stable/c/48f72aff24f7a7329209dc6cbc27c869f3e3595c'
  - url: 'https://git.kernel.org/stable/c/6703199f4d7e7f37d6a726a849eb358e8fae72fb'
  - url: 'https://git.kernel.org/stable/c/19413ccc45070a7270b9e25c2a258daf7f91de42'
  - url: 'https://git.kernel.org/stable/c/fca26a3fc19ed02278aa2a150af82d43db0302cb'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89690.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89690'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532103'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89690'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89690'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89690.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00163
epssPercentile: 0.05463
scores:
  cna: 7.8
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

nfsd: defer vfree of compound ops to fix rpc_status UAF

The rpc_status netlink dumpit walks every in-flight svc_rqst under
rcu_read_lock and, for NFSv4 requests, reads opnums out of
args->ops[]. But args->ops is a separate vmalloc buffer freed
synchronously by vfree() in nfsd4_release_compoundargs() at the end
of every compound. The dumpit's rcu_read_lock pins the svc_rqst
struct itself (freed via kfree_rcu), but nothing defers the vfree
of the ops buffer across the RCU grace period. A concurrent compound
completion can therefore free the buffer while the dumpit is reading
it — a use-after-free on vmalloc memory.

The trailing seqcount recheck (smp_load_acquire of rq_status_counter)
cannot undo a load that already retired against freed memory.

Fix by replacing vfree(args->ops) with kvfree_rcu_mightsleep(), which
defers the free until after an RCU grace period. This makes the
existing rcu_read_lock in the dumpit sufficient to protect the read.
The tradeoff is that completed compound ops buffers (up to
200 * sizeof(struct nfsd4_op)) persist in memory slightly longer,
across one grace period, before being reclaimed.

## Affected

- `Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c < 48f72aff24f7a7329209dc6cbc27c869f3e3595c`
- `Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c < 6703199f4d7e7f37d6a726a849eb358e8fae72fb`
- `Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c < 19413ccc45070a7270b9e25c2a258daf7f91de42`
- `Linux >= bd9d6a3efa9709e653aafbeb859289feccb8e70c < fca26a3fc19ed02278aa2a150af82d43db0302cb`
- `Linux 6.7`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89690.json)