Unknown

CVE-2026-89683 — nfsd: fix dentry ref leak on V4ROOT export filehandle lookup

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.

Published Sep 11, 2026 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.18%

ahead of 7% of scored CVEs · Oct 22, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 and < d493cf57f4c4dae5396cd6ad41e5c209d0615a81≥ ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 and < c1ae0f973bcba5730871e35976a0ab6878fdac34≥ ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 and < 11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca≥ ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 and < 6247023fbbec1325029f2d5f2a7cdc0f9f9ea15aversion 6.12	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 22, 2026 · 7 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 16, 2026
Affected products added · linux/linux
Oct 16, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 11, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 19, 2026 – Oct 19, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

6 on the record

git.kernel.org/stable/c/6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-89683
GitHub Security Advisories
git.kernel.org/stable/c/c1ae0f973bcba5730871e35976a0ab6878fdac34
NIST National Vulnerability Database
git.kernel.org/stable/c/d493cf57f4c4dae5396cd6ad41e5c209d0615a81
NIST National Vulnerability Database
git.kernel.org/stable/c/11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca
NIST National Vulnerability Database
github.com/advisories/GHSA-58hv-jwv2-hff3
GitHub Security Advisories

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-98869 bpf: Infer zext_dst based on static register liveness analysis 1d
Unknown CVE-2023-7356 Bluetooth: ISO: Copy BASE if service data matches EIR_BAA_SERVICE_UUID 1d
Unknown CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 4d
Unknown CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 4d
Unknown CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 4d
Unknown CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 4d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-89683 is "nfsd: fix dentry ref leak on V4ROOT export filehandle lookup", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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