# sunrpc: fix use-after-free in \_\_rpc_clnt_handle_event and \_\_rpc_clnt_remove_pipedir

CVE record · `CVE-2026-89543`

- **Identifiers:** `CVE-2026-89543`
- **State:** Confirmed
- **Severity:** No CVSS score
- **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, 19:44 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: `7749fd2dbef72a52b5c9ffdbf877691950ed4680 to before 1a713814e0580f946196bca5e340b37991c6e8bf` (git)
  - affected: `cc2e7ebbeb1d0601f7f3c8d93b78fcc03a95e44a to before f99fedfd1dbffe8d20b421c9a7d4655a135d4fcd` (git)
  - affected: `bfca5fb4e97c46503ddfc582335917b0cc228264 to before 59527bbfb1eabdb28e95e7c725886cc2c2899cb3` (git)
  - affected: `bfca5fb4e97c46503ddfc582335917b0cc228264 to before e769fcde3cc73e847b1eb3acd40c04a291cb0c0c` (git)
  - affected: `bfca5fb4e97c46503ddfc582335917b0cc228264 to before cdf7a233cb94774b0e7df42d9157077983f5022c` (git)
  - affected: `bfca5fb4e97c46503ddfc582335917b0cc228264 to before 932a8cf6abb2b2f8677b79153a823108d8861fe2` (git)
  - affected: `17866066b8ac1cc38fb449670bc15dc9fee4b40a` (git)
  - affected: `7d61d1da2ed1f682c41cae0c8d4719cdaccee5c5` (git)
  - affected: `dedf2a0eb9448ae73b270743e6ea9b108189df46` (git)
  - affected: `194454afa6aa9d6ed74f0c57127bc8beb27c20df` (git)
  - affected: `1cdb52ffd6600a37bd355d8dce58ecd03e55e618` (git)
  - affected: `6.1.64 to before 6.1.191` (semver)
  - and 6 more
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `6.7`
  - unaffected: `before 6.7` (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: `6.18.50 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

## Machine-written summary

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

> The Linux kernel's sunrpc subsystem is affected in versions from 6.7 onward, with fixes in several stable branches (6.1.191, 6.6.160, 6.12.111, 6.18.50 and later point releases). A use-after-free can occur after a late pipefs mount or a remount, when stale superblock state leaves pipefs entries pointing at a freed RPC client. The source gives few details on the attacker's access requirements or impact. Upgrade to a fixed kernel version for your branch; no workaround is listed.

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

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0021, the 11th 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-2026-89543](https://www.cve.org/CVERecord?id=CVE-2026-89543)
- [NVD: CVE-2026-89543](https://nvd.nist.gov/vuln/detail/CVE-2026-89543)

### References from the CNA

- <https://git.kernel.org/stable/c/1a713814e0580f946196bca5e340b37991c6e8bf>
- <https://git.kernel.org/stable/c/f99fedfd1dbffe8d20b421c9a7d4655a135d4fcd>
- <https://git.kernel.org/stable/c/59527bbfb1eabdb28e95e7c725886cc2c2899cb3>
- <https://git.kernel.org/stable/c/e769fcde3cc73e847b1eb3acd40c04a291cb0c0c>
- <https://git.kernel.org/stable/c/cdf7a233cb94774b0e7df42d9157077983f5022c>
- <https://git.kernel.org/stable/c/932a8cf6abb2b2f8677b79153a823108d8861fe2>

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-2026-89543>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89543/>. Everything for agents: <https://agentprime.io/llms.txt>.