NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock
Published Sep 11, 2026
9.8
CRITICALCVSS 3.1
EPSS 0.71%
Description
nfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with list_for_each_entry_safe(ni, tmp, ...). For each expired entry it sets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the source vfsmount, then reacquires the lock to list_del + kfree the entry and continue iterating via the macro's saved tmp pointer.
The nsui_busy flag protects the current ni from concurrent nfsd4_ssc_setup_dul() finders during the lock-drop window, but it does not pin tmp. Another nfsd RPC thread that fails its source- server mount and reaches nfsd4_ssc_cancel_dul() will, during that same window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount item, and release the lock. If that item is the saved tmp of the expire walk, the next iteration dereferences a freed nfsd4_ssc_umount_item.
Restart the walk from the head after the mntput() unlock window so no saved next pointer survives the lock-drop. The list is bounded by the number of active inter-server source mounts (typically small) and the expire delayed-work runs periodically rather than per-IO, so the restart is cheap.
Affected products
-
Affected
- ≥ 5.10.220, < 5.10.270
-
Affected
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
- ≥ , <
-
Affected
- 5.14
Unaffected
- ≥ 0, < 5.14
- ≥ 5.10.270, ≤ 5.10.*
- ≥ 5.15.221, ≤ 5.15.*
- ≥ 6.1.188, ≤ 6.1.*
- ≥ 6.12.109, ≤ 6.12.*
- ≥ 6.18.50, ≤ 6.18.*
- ≥ 6.6.157, ≤ 6.6.*
- ≥ 7.2.4, ≤ 7.2.*
- 7.3-rc1
Default status is the baseline for the product. Each version can override it (patched versions can be marked unaffected).
| Vendor | Product | Default status | Versions |
|---|---|---|---|
| Linux | Linux | unaffected | Affected
|
| Linux | Linux | unaffected | Affected
|
| Linux | Linux | affected | Affected
Unaffected
|
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
Out of support scope
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not 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
Not 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 | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not 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 | Not 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.
References (14)
- https://access.redhat.com/security/cve/CVE-2026-89712 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2532255 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-76624 Advisory
- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89712.mbox
- https://git.kernel.org/stable/c/036c1b182f4da65363e79ec0ac276edc6b7296e5
- https://git.kernel.org/stable/c/2b59029b8f24a99b5d844af2da3950d39d36eeea
- https://git.kernel.org/stable/c/4ed8d2317aef21cc2a9e5a55d6b59860b4b151a8
- https://git.kernel.org/stable/c/60680ae7243b22de3d09be990d8e23bcfc4af837
- https://git.kernel.org/stable/c/659ee3da073164e1e6e40dfcbc26eeed85845f93
- https://git.kernel.org/stable/c/7377fa964b8aaf47cb04e5efcc4c82d15e8c2ce9
- https://git.kernel.org/stable/c/77de363d9a1c8cd35f20482782c612cda085791a
- https://git.kernel.org/stable/c/d9e151fea5ed706c1284adacabd869b0be745db2
- https://nvd.nist.gov/vuln/detail/CVE-2026-89712
- https://www.cve.org/CVERecord?id=CVE-2026-89712
Change history (0)
No recorded changes yet.
CVE.org / MITRE
CISA Vulnrichment
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GitHub
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