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NVD / CVE Program· CNA Linux

CVE-2026-89715: NFS/localio: fix ref leak on nfs_uuid_add_file failure

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 5215e734bf7cba18237155f8cb2a0accb60ca339, 6.16, 6.17.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 5215e734bf7cba18237155f8cb2a0accb60ca339, 6.16, 6.17 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: NFS/localio: fix ref leak on nfs_uuid_add_file failure When nfs_uuid_add_file() races with nfs_uuid_put() tearing down uuid->net, it returns -ENXIO without publishing nfl->nfs_uuid via rcu_assign_pointer(). nfs_open_local_fh() then enters its error branch and only releases the slot's file ref and its paired net ref plus its own entry-time net ref, while the close path is a no-op: nfs_close_local_fh() nfs_uuid = rcu_dereference(nfl->nfs_uuid); if (!nfs_uuid) { rcu_read_unlock(); return; } /* always */ nfsd_open_local_fh() returns localio holding a caller-owned +1 nfsd_file reference (from nfsd_file_get() after nfsd_file_acquire_local()) and an entry-time nfsd_net reference (from its first nfsd_net_try_get()) embedded as nf->nf_net. Both are leaked on the failure path, pinning one nfsd_file (and the underlying struct file, dentry, inode) and one nfsd_net_ref per occurrence, which blocks nfsd_net and netns teardown. Fix by releasing the caller-owned file ref and its net ref through the existing helper, using a stack-local RCU pointer so the helper can xchg it out, then returning -ENXIO so callers do not dereference a localio whose slot has been cleared: struct nfsd_file __rcu *tmp = RCU_INITIALIZER(localio); nfs_to_nfsd_file_put_local(pnf); nfs_to_nfsd_file_put_local(&tmp); localio = ERR_PTR(-ENXIO); The trailing nfs_to_nfsd_net_put(net) continues to release the outer net ref, so all three nfsd_net_try_get() increments are balanced on the error branch.

—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 55735dc5a0ee0c0fc14cb51e005eae862906a410, 7cac8a129fc53497f9ee5d66fca55a245d009b97, 6.17affected
    • fdd015de767977f21892329af5e12276eb80375f and later · before 5215e734bf7cba18237155f8cb2a0accb60ca339affected · git
    • fdd015de767977f21892329af5e12276eb80375f and later · before 9f59b05423ed381f8cdeaaae4bd6778adcb6865caffected · git
    • fdd015de767977f21892329af5e12276eb80375f and later · before ca018c19e0ba38975e5ddc3ef8117d5b734313aaaffected · git
    • 6.15.10 and later · before 6.16affected · semver
    • 6.16.1 and later · before 6.17affected · semver
    • before 6.17not affected · semver
    • 6.18.50 and later · up to and including 6.18.*not affected · semver
    • 7.2.4 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-89713Sep 11, 2026 · NFSD: check truncate permission under inode lock
    36Monitor
  • ← EarlierCVE-2026-89714Sep 11, 2026 · NFS: fix delegation_hash_table leak when nfs4_server_common_setup() fails
    0Monitor
  • Later →CVE-2026-89716Sep 11, 2026 · zram: validate deflate params
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5215e734bf7cba18237155f8cb2a0accb60ca339Vendor (CNA)
Linux Linux6.16Vendor (CNA)
Linux Linux6.17Vendor (CNA)
Linux Linux9f59b05423ed381f8cdeaaae4bd6778adcb6865cVendor (CNA)
Linux Linuxca018c19e0ba38975e5ddc3ef8117d5b734313aaVendor (CNA)
debian:linux7.2.6-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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