# NFSD: Prevent client use-after-free during delegation revoke

CVE record · `CVE-2026-89659`

- **Identifiers:** `CVE-2026-89659`
- **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:** 30 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: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 2f9a200c0ea5b214609b8cea2b6666458bcb54cd` (git)
  - affected: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 94f0c73797c30a35812ffb32d11b8737d245c405` (git)
  - affected: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 0dd276b1324a5e08e83c6f675919946c9f0d61c9` (git)
  - affected: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3` (git)
  - affected: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56` (git)
  - affected: `3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 to before 4683ca76b3b7e5808338491c6eb3c20e6b4894d5` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `3.10`
  - unaffected: `before 3.10` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.111 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.51 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:** 0.0048, the 41st 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-2026-89659](https://www.cve.org/CVERecord?id=CVE-2026-89659)
- [NVD: CVE-2026-89659](https://nvd.nist.gov/vuln/detail/CVE-2026-89659)

### References from the CNA

- <https://git.kernel.org/stable/c/2f9a200c0ea5b214609b8cea2b6666458bcb54cd>
- <https://git.kernel.org/stable/c/94f0c73797c30a35812ffb32d11b8737d245c405>
- <https://git.kernel.org/stable/c/0dd276b1324a5e08e83c6f675919946c9f0d61c9>
- <https://git.kernel.org/stable/c/3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3>
- <https://git.kernel.org/stable/c/2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56>
- <https://git.kernel.org/stable/c/4683ca76b3b7e5808338491c6eb3c20e6b4894d5>

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-2026-89659>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89659/>. Everything for agents: <https://agentprime.io/llms.txt>.