# SUNRPC: Reject short RFC 4121 MIC tokens in gss_krb5_verify_mic_v2

CVE record · `CVE-2026-89537`

- **Identifiers:** `CVE-2026-89537`
- **State:** Confirmed
- **Severity:** CVSS 9.1 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, 19:44 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.

## Critical

Critical, because:

- CVSS score 9.1: 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: `de9c17eb4a912c9028f7b470eb80815144883b26 to before 86c3d527303ec79805098bda3dfc4fa994757f59` (git)
  - affected: `de9c17eb4a912c9028f7b470eb80815144883b26 to before b2e9e10f5a536befcdce64d3e6946dff42fb823e` (git)
  - affected: `de9c17eb4a912c9028f7b470eb80815144883b26 to before 997577c52487181226775db3755079a3ba1d52b9` (git)
  - affected: `de9c17eb4a912c9028f7b470eb80815144883b26 to before 996dd15f60121bdd7896b4554458f8806d608063` (git)
  - affected: `de9c17eb4a912c9028f7b470eb80815144883b26 to before 7a946b2e7207f968902f2147ab9b30726f82f7ab` (git)
  - affected: `de9c17eb4a912c9028f7b470eb80815144883b26 to before b94f6719dcd9f7a609bc5f459f85795900e77d25` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.35`
  - unaffected: `before 2.6.35` (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: `6.18.57 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0073, the 54th 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-2026-89537](https://www.cve.org/CVERecord?id=CVE-2026-89537)
- [NVD: CVE-2026-89537](https://nvd.nist.gov/vuln/detail/CVE-2026-89537)

### References from the CNA

- <https://git.kernel.org/stable/c/86c3d527303ec79805098bda3dfc4fa994757f59>
- <https://git.kernel.org/stable/c/b2e9e10f5a536befcdce64d3e6946dff42fb823e>
- <https://git.kernel.org/stable/c/997577c52487181226775db3755079a3ba1d52b9>
- <https://git.kernel.org/stable/c/996dd15f60121bdd7896b4554458f8806d608063>
- <https://git.kernel.org/stable/c/7a946b2e7207f968902f2147ab9b30726f82f7ab>
- <https://git.kernel.org/stable/c/b94f6719dcd9f7a609bc5f459f85795900e77d25>

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-2026-89537>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89537/>. Everything for agents: <https://agentprime.io/llms.txt>.