CVE-2026-89711

Last refreshed2026-10-17

Status: UPDATED | Advisory ID: CVE-2026-89711

Key Details

CVE	CVE-2026-89711
CVSS Score / Version	8.2 (High) / CVSS v3.1
Updated	2026-10-16
CVSS Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`
CVSS Prose	attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is low; integrity impact is none; availability impact is high.
Affected products	Linux Kernel

Vendor	Product	Affected Versions	Patch Status
Linux	Linux Kernel

Vendor

Product

Affected Versions

Patch Status

Linux

Linux Kernel

Subsystems	OT Supporting Infrastructure
Sectors	All Sectors

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

NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check

The header for commit e75b23f9e323 ("nfsd: check d_can_lookup in

fh_verify of directories") details the assumption that justified

adding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is

invalid (in the case of NFS reexport).

When NFSD exports an NFS filesystem it is very possible for

nfsd_mode_check() to encounter a @dentry that doesn't have

i_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and

NFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).

So remove nfsd_mode_check()'s WARN_ON_ONCE(). The nfserr_notdir

return on that branch must stay. It guards the subsequent

lookup_one_unlocked() -> __lookup_slow() path, which calls

inode->i_op->lookup() with no NULL check, so returning nfserr_notdir

is what keeps a client LOOKUP into such a @dentry from dereferencing

a NULL method pointer. (NVD)

Monitor Linux's web page for any future patch releases.

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-89711
CVE	https://www.cve.org/CVERecord?id=CVE-2026-89711

Source

Reference

NVD

CVE