# ksmbd: fix tree connection use-after-free in smb2_tree_connect()

CVE record · `CVE-2026-89788`

- **Identifiers:** `CVE-2026-89788`
- **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:** 16 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 16 Sept 2026, 08:48 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: `7b58ee8d0b91359554cf219cd4f33872ea2afd66 to before 63f5939b50470ef4d245c16d2098376b952beb51` (git)
  - affected: `33b235a6e6ebe0f05f3586a71e8d281d00f71e2e to before ca3a3984bf445aaec69f6937f11e560d4b849365` (git)
  - affected: `33b235a6e6ebe0f05f3586a71e8d281d00f71e2e to before bd58a52738f7576ee5f5eb74243df13f902c8051` (git)
  - affected: `33b235a6e6ebe0f05f3586a71e8d281d00f71e2e to before 4e30fbd26e84efa2e5cbec4eb11e126ac0c79313` (git)
  - affected: `33b235a6e6ebe0f05f3586a71e8d281d00f71e2e to before b5ec6c462aab1062cf5d1e667ba7c6442f737055` (git)
  - affected: `dd45db4d9bbc8f122a9b4db5ce94ae29fcf03d3c` (git)
  - affected: `6.1.71 to before 6.1.191` (semver)
  - affected: `5.15.145 to before 5.16` (semver)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `6.6`
  - unaffected: `before 6.6` (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: `7.2.6 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:** 0.0064, the 51st 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 16 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89788](https://www.cve.org/CVERecord?id=CVE-2026-89788)
- [NVD: CVE-2026-89788](https://nvd.nist.gov/vuln/detail/CVE-2026-89788)

### References from the CNA

- <https://git.kernel.org/stable/c/63f5939b50470ef4d245c16d2098376b952beb51>
- <https://git.kernel.org/stable/c/ca3a3984bf445aaec69f6937f11e560d4b849365>
- <https://git.kernel.org/stable/c/bd58a52738f7576ee5f5eb74243df13f902c8051>
- <https://git.kernel.org/stable/c/4e30fbd26e84efa2e5cbec4eb11e126ac0c79313>
- <https://git.kernel.org/stable/c/b5ec6c462aab1062cf5d1e667ba7c6442f737055>

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-2026-89788>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89788/>. Everything for agents: <https://agentprime.io/llms.txt>.