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NVD / CVE Program· CNA Linux

CVE-2026-89690: nfsd: defer vfree of compound ops to fix rpc_status UAF

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 19413ccc45070a7270b9e25c2a258daf7f91de42, 48f72aff24f7a7329209dc6cbc27c869f3e3595c, 6703199f4d7e7f37d6a726a849eb358e8fae72fb.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 19413ccc45070a7270b9e25c2a258daf7f91de42, 48f72aff24f7a7329209dc6cbc27c869f3e3595c, 6703199f4d7e7f37d6a726a849eb358e8fae72fb 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: defer vfree of compound ops to fix rpc_status UAF The rpc_status netlink dumpit walks every in-flight svc_rqst under rcu_read_lock and, for NFSv4 requests, reads opnums out of args->ops[]. But args->ops is a separate vmalloc buffer freed synchronously by vfree() in nfsd4_release_compoundargs() at the end of every compound. The dumpit's rcu_read_lock pins the svc_rqst struct itself (freed via kfree_rcu), but nothing defers the vfree of the ops buffer across the RCU grace period. A concurrent compound completion can therefore free the buffer while the dumpit is reading it — a use-after-free on vmalloc memory. The trailing seqcount recheck (smp_load_acquire of rq_status_counter) cannot undo a load that already retired against freed memory. Fix by replacing vfree(args->ops) with kvfree_rcu_mightsleep(), which defers the free until after an RCU grace period. This makes the existing rcu_read_lock in the dumpit sufficient to protect the read. The tradeoff is that completed compound ops buffers (up to 200 * sizeof(struct nfsd4_op)) persist in memory slightly longer, across one grace period, before being reclaimed.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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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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

    • 6.7affected
    • bd9d6a3efa9709e653aafbeb859289feccb8e70c and later · before 48f72aff24f7a7329209dc6cbc27c869f3e3595caffected · git
    • bd9d6a3efa9709e653aafbeb859289feccb8e70c and later · before 6703199f4d7e7f37d6a726a849eb358e8fae72fbaffected · git
    • bd9d6a3efa9709e653aafbeb859289feccb8e70c and later · before 19413ccc45070a7270b9e25c2a258daf7f91de42affected · git
    • bd9d6a3efa9709e653aafbeb859289feccb8e70c and later · before fca26a3fc19ed02278aa2a150af82d43db0302cbaffected · git
    • before 6.7not affected · semver
    • 6.12.109 and later · up to and including 6.12.*not 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
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-2026-89688Sep 11, 2026 · nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
    39Monitor
  • ← EarlierCVE-2026-89689Sep 11, 2026 · nfsd: don't free session slots that are still in use
    39Monitor
  • Later →CVE-2026-89691Sep 11, 2026 · nfsd: clear opcnt on compound arg release to prevent OOB read
    28Monitor

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 Linux19413ccc45070a7270b9e25c2a258daf7f91de42Vendor (CNA)
Linux Linux48f72aff24f7a7329209dc6cbc27c869f3e3595cVendor (CNA)
Linux Linux6703199f4d7e7f37d6a726a849eb358e8fae72fbVendor (CNA)
Linux Linuxfca26a3fc19ed02278aa2a150af82d43db0302cbVendor (CNA)
almalinux:kernel5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.56.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.64.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.56.1.el9_8 · AlmaLinux:9Package 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)

+13

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/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. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records