nfsd: fix dentry ref leak on V4ROOT export filehandle lookup (CVE-2026-89683) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89683

nfsd: fix dentry ref leak on V4ROOT export filehandle lookup

Answer in brief

CVE-2026-89683 records a Unknown severity vulnerability in nfsd: fix dentry ref leak on V4ROOT export filehandle lookup. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <d493cf57f4c4dae5396cd6ad41e5c209d0615a81 \|\| >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <c1ae0f973bcba5730871e35976a0ab6878fdac34 \|\| >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca \|\| >=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a	d493cf57f4c4dae5396cd6ad41e5c209d0615a81, c1ae0f973bcba5730871e35976a0ab6878fdac34, 11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca, 6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a
Linux/Linuxgeneric	6.12	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to d493cf57f4c4dae5396cd6ad41e5c209d0615a81 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix dentry ref leak on V4ROOT export filehandle lookup nfsd_set_fh_dentry() leaks the dentry reference from exportfs_decode_fh_raw() when the NFS3_FHSIZE or NFS_FHSIZE switch cases detect NFSEXP_V4ROOT and goto out. The out: label calls exp_put() but never dput(dentry), and fhp->fh_dentry was never assigned so fh_put() cannot compensate. A crafted NFSv3 filehandle targeting a V4ROOT export's fsid triggers the leak on every request.

Quoted source text, attributed separately from HOL analysis.