CVE-2026-89677

nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()

CRITICAL
9.8
CVSS Score
Published: September 11, 2026 at 07:46 PM UTC
Updated: October 19, 2026 at 09:18 AM UTC
1 product affected across 1 vendorLinux Kernel

Using Linux by Linux?

Get instant alerts when new vulnerabilities affect Linux - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
CRITICAL9.8
Exploit prediction
EPSS 0.6%

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file() dentry_create() can hypothetically provide a different dentry than the one passed in. This could happen, for example, if the exported filesystem is NFS, and the server returned to OPEN a filehandle which matched a directory that was already in the dcache. Clearly this would not be expected! If this were to happen the dentry (child) that was already stored in resfhp could be freed and later dereferenced. We shouldn't call fh_compose() until we are certain that we have the final dentry, so this patch moved the fh_compose() call to two places: one for the case where the target already exists, and one after dentry_create() where it was created.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

64a989dbd144e0622371396461b11335459692d27.0
Vendor states this is fixed in 033e783709ce99662cf81f6abcad746a8da9d35f (fixed)
Vendor states this is fixed in 3e2c79360c6a89975ec5b5a7d4ef937e4db91a27 (fixed)
Vendor states this is fixed in 7.0 (unaffected)
Vendor states this is fixed in 7.2.4 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

9.8CRITICALLinux
Vector?

Quick Info

StatusRECEIVED

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card