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NVD / CVE Program· CNA Linux

CVE-2026-89676: nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.49% (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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 14b978e8d05ce018d0afbeb6611833ef91713a02, 745b2edfdd96b8738a94dee450adff4c7d026d5b, 7aa34ea78f74e6ef60c8112635a87fc43d57f6c9.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 14b978e8d05ce018d0afbeb6611833ef91713a02, 745b2edfdd96b8738a94dee450adff4c7d026d5b, 7aa34ea78f74e6ef60c8112635a87fc43d57f6c9 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 stale s2s_cp_stateids IDR entry for async COPY For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find(). Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 30, 2026
EPSS
0.4% · 42th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
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

    • 4.20affected
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before 745b2edfdd96b8738a94dee450adff4c7d026d5baffected · git
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before bdce362f49410b9def65d76c21f6259cd89696d8affected · git
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before 7aa34ea78f74e6ef60c8112635a87fc43d57f6c9affected · git
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before 9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7aaffected · git
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before 14b978e8d05ce018d0afbeb6611833ef91713a02affected · git
    • e0639dc5805a9d4faaa2c07ad98fa853b9529dd3 and later · before d0beaee498e11880e72826026db0e9c9890fc114affected · git
    • before 4.20not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.64.1.el10_26.12.0-211.64.1.el10_2

+96

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-2026-89674Sep 11, 2026 · nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
    39Monitor
  • ← EarlierCVE-2026-89675Sep 11, 2026 · nfsd: fix UAF in async copy cancel and shutdown
    39Monitor
  • Later →CVE-2026-89677Sep 11, 2026 · nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
    39Monitor

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 Linux14b978e8d05ce018d0afbeb6611833ef91713a02Vendor (CNA)
Linux Linux745b2edfdd96b8738a94dee450adff4c7d026d5bVendor (CNA)
Linux Linux7aa34ea78f74e6ef60c8112635a87fc43d57f6c9Vendor (CNA)
Linux Linux9b4e5e9ba5ae13808b8a6d229d87c54611ba0e7aVendor (CNA)
Linux Linuxbdce362f49410b9def65d76c21f6259cd89696d8Vendor (CNA)
Linux Linuxd0beaee498e11880e72826026db0e9c9890fc114Vendor (CNA)
almalinux:kernel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debuginfo0:6.12.0-211.64.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+3

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

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (5 more)

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

All records