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NVD / CVE Program· CNA Linux

CVE-2026-89684: nfsd: fix cpntf publish race in nfs4_init_cp_state

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.50% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 21d6c5957f5ca97d7352e60f55ea412beb9419f5, 63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3, 6ac469a274e3c7d87fc46ba46d83b95009680407.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 21d6c5957f5ca97d7352e60f55ea412beb9419f5, 63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3, 6ac469a274e3c7d87fc46ba46d83b95009680407 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: nfsd: fix cpntf publish race in nfs4_init_cp_state nfs4_alloc_init_cpntf_state() published the new cpntf entry into the s2s_cp_stateids IDR (with cs_type set) in one s2s_cp_lock section, then took the lock again to list_add() it onto p_stid->sc_cp_list. In the gap the entry is reachable by so_id but cp_list is still {NULL,NULL} from kzalloc. A racing OFFLOAD_CANCEL (so_id is echoed to the client as cnr_stateid, so any NFSv4.2 client can drive it) reaches manage_cpntf_state() -> _free_cpntf_state_locked() and does list_del() on the zeroed list_head, oopsing the server. Fold the cs_type assignment and the list_add() into the same critical section as idr_alloc_cyclic(), so a concurrent lookup either misses the entry or sees a fully linked cp_list. INIT_LIST_HEAD() the entry after allocation and switch _free_cpntf_state_locked() to list_del_init() so a stale unlink is a no-op. nfs4_init_copy_state() passes NULL p_stid and skips the list_add, preserving NFS4_COPY_STID semantics.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 19, 2026
EPSS
0.5% · 42th percentile
CWE
—

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

    • 5.6affected
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before 63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3affected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before 6ac469a274e3c7d87fc46ba46d83b95009680407affected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before 8eeca993357a0bc35aaefebfd7462ac7b0a21d9aaffected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before bfeac42d9074e539bacd1898dd8c14b7f5776620affected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before 21d6c5957f5ca97d7352e60f55ea412beb9419f5affected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before a631a26a8777bb235eabd478bbbaf26a4db750bfaffected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before c7270f62e7a05a2ee68aa2b74262b658a14463bdaffected · git
    • 624322f1adc58acd0b69f77a6ddc764207e97241 and later · before be3a5c1d857b0dcbc11796cea603ef25834f75b2affected · git
    • before 5.6not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
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-2026-89682Sep 11, 2026 · nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net
    32Monitor
  • ← EarlierCVE-2026-89683Sep 11, 2026 · nfsd: fix dentry ref leak on V4ROOT export filehandle lookup
    0Monitor
  • Later →CVE-2026-89685Sep 11, 2026 · nfsd: fix clock domain mismatch in clients_still_reclaiming()
    30Monitor

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 Linux21d6c5957f5ca97d7352e60f55ea412beb9419f5Vendor (CNA)
Linux Linux63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3Vendor (CNA)
Linux Linux6ac469a274e3c7d87fc46ba46d83b95009680407Vendor (CNA)
Linux Linux8eeca993357a0bc35aaefebfd7462ac7b0a21d9aVendor (CNA)
Linux Linuxa631a26a8777bb235eabd478bbbaf26a4db750bfVendor (CNA)
Linux Linuxbe3a5c1d857b0dcbc11796cea603ef25834f75b2Vendor (CNA)
Linux Linuxbfeac42d9074e539bacd1898dd8c14b7f5776620Vendor (CNA)
Linux Linuxc7270f62e7a05a2ee68aa2b74262b658a14463bdVendor (CNA)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package 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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

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✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

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

All records