# CVE-2026-89788

ksmbd use-after-free in smb2_tree_connect allows remote kernel compromise via SMB

- Page: https://www.vulneraibility.com/cve/CVE-2026-89788
- CVSS: 9.8
- Known exploited: not in CISA KEV as of our last sync
- EPSS: 0.65% (percentile 51.3)
- Published: 2026-09-16

## Affected versions

- Linux: affected >= 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e and < 4e30fbd26e84efa2e5cbec4eb11e126ac0c79313; >= 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e and < b5ec6c462aab1062cf5d1e667ba7c6442f737055; dd45db4d9bbc8f122a9b4db5ce94ae29fcf03d3c; 7b58ee8d0b91359554cf219cd4f33872ea2afd66; >= 5.15.145 and < 5.16; >= 6.1.71 and < 6.2; 6.6; fixed in < 6.6, >= 7.2.6 and <= 7.2.*, >= 7.3-rc2 and <= *

A version outside these ranges is not a statement that it is unaffected.

## Impact

Remote code execution or kernel crash via crafted SMB2 TREE_CONNECT; attacker can achieve kernel-level compromise or DoS on exposed SMB servers.

## Action

Immediate action required

## Recommendation

Apply vendor kernel updates or backported ksmbd patch; block/limit SMB exposure until patched.

## References

- [other] https://git.kernel.org/stable/c/63f5939b50470ef4d245c16d2098376b952beb51
- [other] https://git.kernel.org/stable/c/ca3a3984bf445aaec69f6937f11e560d4b849365
- [other] https://git.kernel.org/stable/c/bd58a52738f7576ee5f5eb74243df13f902c8051
- [other] https://git.kernel.org/stable/c/4e30fbd26e84efa2e5cbec4eb11e126ac0c79313
- [other] https://git.kernel.org/stable/c/b5ec6c462aab1062cf5d1e667ba7c6442f737055

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.