# NFSD: Prevent lock owner use-after-free during client teardown

CVE record · `CVE-2026-89662`

- **Identifiers:** `CVE-2026-89662`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:45 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before 42d7954b0a1907d4ef122aef94561952a033cdc3` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before b8bad5a11416b26cc7fd4b18fba46d75ff636558` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before 1ce74d1b7770e69735e8f8e509807af4ff9c8ee7` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before a6ead6fff3a7d03e49845f048f7000a2e0d34431` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before 4804c58f73a80d12df1de323bf97a164f6ee8743` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before 8cf4ff0a7c083dd5e0067f517d63979b74b66649` (git)
  - affected: `68ef3bc3166468678d5e1fdd216628c35bd1186f to before 5e2fa29d223a9a1e6a948e40b109d09081d1decd` (git)
  - affected: `e294c4c2d33b7307a89cdf31bec08a112d6a9297` (git)
  - affected: `797bfd05d4040fbf766198b3cfcc1838002cc890` (git)
  - affected: `0f44e9da465ea259b6c9f31a627f3c50a16e1679` (git)
  - affected: `4.9.91 to before 4.10` (semver)
  - and 2 more
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.16`
  - unaffected: `before 4.16` (semver)
  - unaffected: `5.10.270 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.221 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.188 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.157 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.109 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.50 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.4 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 9.8 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0069, the 53rd percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 11 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89662](https://www.cve.org/CVERecord?id=CVE-2026-89662)
- [NVD: CVE-2026-89662](https://nvd.nist.gov/vuln/detail/CVE-2026-89662)

### References from the CNA

- <https://git.kernel.org/stable/c/42d7954b0a1907d4ef122aef94561952a033cdc3>
- <https://git.kernel.org/stable/c/bb38ff8b4dafbbd1781ad37cd96722fdf2cd972a>
- <https://git.kernel.org/stable/c/b8bad5a11416b26cc7fd4b18fba46d75ff636558>
- <https://git.kernel.org/stable/c/1ce74d1b7770e69735e8f8e509807af4ff9c8ee7>
- <https://git.kernel.org/stable/c/a6ead6fff3a7d03e49845f048f7000a2e0d34431>
- <https://git.kernel.org/stable/c/4804c58f73a80d12df1de323bf97a164f6ee8743>
- <https://git.kernel.org/stable/c/8cf4ff0a7c083dd5e0067f517d63979b74b66649>
- <https://git.kernel.org/stable/c/5e2fa29d223a9a1e6a948e40b109d09081d1decd>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-89662>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89662/>. Everything for agents: <https://agentprime.io/llms.txt>.