CVE Intelligence
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CVE-2026-89714 — NFS: fix delegation_hash_table leak when nfs4_server_common_setup() fails

In the Linux kernel, the following vulnerability has been resolved: NFS: fix delegation_hash_table leak when nfs4_server_common_setup() fails nfs4_server_common_setup() allocates server->delegation_hash_table first, but server->destroy - the only path that frees the table via nfs4_destroy_server() - is not assigned until the very end of the function. If any intermediate step fails (the is_ds_only_client() check, nfs4_init_session(), nfs4_get_rootfh(), or nfs_probe_server()), the function returns with server->destroy still NULL, so the caller's nfs_free_server() skips the destroy callback and the hash table is leaked (4 KiB per attempt with the default delegation watermark). This is trivially reachable from userspace: every failed NFSv4 mount leaks one allocation. A client that persistently retries a mount that cannot succeed leaks kernel memory without bound. Observed in production where a Longhorn backup poller retried mount.nfs4 against an NFSv3-only server roughly 10 times per second, leaking ~3.4 GiB of unreclaimable slab (kmalloc-rnd-13-4k) per day; the node accumulated 12 GiB of leaked slab before the source was identified via the kmem:kmalloc tracepoint (call_site=nfs4_delegation_hash_alloc). Reproducer: # server exports NFSv3 only (or export path absent for v4) while :; do mount -t nfs4 <server>:/missing /mnt; done # watch SUnreclaim in /proc/meminfo grow 4 KiB per iteration Free the table on the error paths between the allocation and the assignment of server->destroy.

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

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)+2

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
0.21%
ahead of 10% of scored CVEs · Oct 20, 2026
Affects
Linux
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.

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

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ f5b3108e6a14418b120a3c38ca589b8d6cf87627 and < f3adf1643517357221422c05986d6de5df7b9913≥ f5b3108e6a14418b120a3c38ca589b8d6cf87627 and < 0fd2b9687dae36be5b84eab39b4c627bb7ab33b3≥ f5b3108e6a14418b120a3c38ca589b8d6cf87627 and < 2092f5b38f88be306140c77aeeeb43fc1adacaccversion 6.17 Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 20, 2026 · 5 reading(s) · max 0.21%

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 15, 2026
  • Affected products added · linux/linux
    Oct 15, 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

5 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-98869 bpf: Infer zext_dst based on static register liveness analysis 6h
  • CVE-2023-7356 Bluetooth: ISO: Copy BASE if service data matches EIR_BAA_SERVICE_UUID 6h
  • CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 3d
  • CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 3d
  • CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 3d
  • CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 3d

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-2026-89714 is "NFS: fix delegation_hash_table leak when nfs4_server_common_setup() fails", 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 0.21% 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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