---
id: CVE-2026-89692
title: 'nfsd: clear CALLBACK_RUNNING on failed delegation recall queue'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nfsd: clear CALLBACK_RUNNING on failed delegation recall queue

  nfsd_break_one_deleg() sets NFSD4_CALLBACK_RUNNING via test_and_set_bit
  at entry to serialize recall wor…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-911
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 <
    b137930ee52e3ef38915a3511d4c070463b63a32
  - >-
    Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 <
    cb2d0c4d1b3d301d042ed61365eaa8cb0141a254
  - >-
    Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 <
    b036727d334b1b7cd4c1f1fba3b59ba93a6bbe96
  - Linux 6.15
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:51:05.555Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89692'
references:
  - url: 'https://git.kernel.org/stable/c/b137930ee52e3ef38915a3511d4c070463b63a32'
  - url: 'https://git.kernel.org/stable/c/cb2d0c4d1b3d301d042ed61365eaa8cb0141a254'
  - url: 'https://git.kernel.org/stable/c/b036727d334b1b7cd4c1f1fba3b59ba93a6bbe96'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89692.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89692'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532481'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89692'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89692'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89692.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00609
epssPercentile: 0.48945
scores:
  cna: 7.5
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

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

nfsd: clear CALLBACK_RUNNING on failed delegation recall queue

nfsd_break_one_deleg() sets NFSD4_CALLBACK_RUNNING via test_and_set_bit
at entry to serialize recall work, then calls nfsd4_run_cb() to queue
the recall.  When the queue attempt fails the refcount bump is undone,
but the RUNNING bit is left set.  The only site that clears the bit is
nfsd41_destroy_cb() (fs/nfsd/nfs4callback.c), which runs from the
workqueue and is therefore unreachable when nothing was queued.

The bit becomes a permanent latch on dp->dl_recall.cb_flags: every
subsequent break_lease() on the same delegation hits the early-return
guard in nfsd_break_one_deleg() and silently skips the recall, so the
delegation is never broken and the conflicting open or lock stalls.

Fix by clearing NFSD4_CALLBACK_RUNNING on the !queued branch alongside
the refcount_dec.

## Affected

- `Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 < b137930ee52e3ef38915a3511d4c070463b63a32`
- `Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 < cb2d0c4d1b3d301d042ed61365eaa8cb0141a254`
- `Linux >= 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 < b036727d334b1b7cd4c1f1fba3b59ba93a6bbe96`
- `Linux 6.15`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89692.json)