# nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net

CVE record · `CVE-2026-89682`

- **Identifiers:** `CVE-2026-89682`
- **State:** Confirmed
- **Severity:** CVSS 8.1 High
- **Critical:** No
- **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, 19:46 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.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before 41fe0e804bbf1110c0aba2ebdfc729efb240d8a6` (git)
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before e6c3a43d0a41f03abae3764fc82a59369360c7e0` (git)
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before 9c8ac7c2b9b150e13b7ad0d0fae54f17747dce67` (git)
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before ba0ee9e04b7a0356c28d5a2fe445db675d24e572` (git)
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before cadc9036d5a8209f89e7026ddba7cfb1c716b03c` (git)
  - affected: `1463b38e7cf34d4cc60f41daff459ad807b2e408 to before bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4` (git)
  - affected: `e8f923e1e9fcc0832a12c8a2461792e5a9544c03` (git)
  - affected: `3bc94fb44f10ef852723e1aeaac6794c5ab16aec` (git)
  - affected: `5.10.220 to before 5.11` (semver)
  - affected: `5.15.154 to before 5.16` (semver)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.17`
  - unaffected: `before 5.17` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.114 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

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Linux kernel versions from 5.17 until their fixes have a use-after-free in the nfsd NFS server's file cache teardown, where a freed structure can still be used by background callbacks. The source gives few details on what an attacker needs to trigger it or what they can do. Upgrade to 6.1.191, 6.6.160, 6.12.114, or 6.18.51 in the matching series, or to a later kernel that includes the fix.

Written 12 Nov 2026.

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0053, the 45th 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-2026-89682](https://www.cve.org/CVERecord?id=CVE-2026-89682)
- [NVD: CVE-2026-89682](https://nvd.nist.gov/vuln/detail/CVE-2026-89682)

### References from the CNA

- <https://git.kernel.org/stable/c/41fe0e804bbf1110c0aba2ebdfc729efb240d8a6>
- <https://git.kernel.org/stable/c/e6c3a43d0a41f03abae3764fc82a59369360c7e0>
- <https://git.kernel.org/stable/c/9c8ac7c2b9b150e13b7ad0d0fae54f17747dce67>
- <https://git.kernel.org/stable/c/ba0ee9e04b7a0356c28d5a2fe445db675d24e572>
- <https://git.kernel.org/stable/c/cadc9036d5a8209f89e7026ddba7cfb1c716b03c>
- <https://git.kernel.org/stable/c/bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4>

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-2026-89682>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89682/>. Everything for agents: <https://agentprime.io/llms.txt>.