# ksmbd: zero pipe read compound padding

CVE record · `CVE-2026-89794`

- **Identifiers:** `CVE-2026-89794`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **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, 10:30 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: `9f297df20d93411c0b4ddad7f88ba04a7cd36e77 to before c7516bdf7d2c1a64b14a9f444e2ee58c12c384ae` (git)
  - affected: `e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to before 134d980491b435e5cdb3171225e2506ff17867d1` (git)
  - affected: `e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to before f188a400dd5285fec5a84548fe8dca49eee01155` (git)
  - affected: `e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to before d83a9de7cecd401c3d3e00ed6371194dcd7313e4` (git)
  - affected: `e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to before be15b8da4a82cf1e1f9880b2661b90770606eec1` (git)
  - affected: `e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d to before 73f860489e3be2245598d1819226304fc5b87291` (git)
  - affected: `f2283680a80571ca82d710bc6ecd8f8beac67d63` (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: `6.12.110 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.51 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.5 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 ksmbd SMB server in the Linux kernel is affected from version 6.6 until fixed. A pipe read in compound responses can expose up to seven bytes of uninitialized kernel heap memory. The source gives few details on the access an attacker needs. Upgrade to 6.1.191, 6.6.160, 6.12.110 or 6.18.51 or later, depending on your branch.

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:** 0.0022, 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 16 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89794](https://www.cve.org/CVERecord?id=CVE-2026-89794)
- [NVD: CVE-2026-89794](https://nvd.nist.gov/vuln/detail/CVE-2026-89794)

### References from the CNA

- <https://git.kernel.org/stable/c/c7516bdf7d2c1a64b14a9f444e2ee58c12c384ae>
- <https://git.kernel.org/stable/c/134d980491b435e5cdb3171225e2506ff17867d1>
- <https://git.kernel.org/stable/c/f188a400dd5285fec5a84548fe8dca49eee01155>
- <https://git.kernel.org/stable/c/d83a9de7cecd401c3d3e00ed6371194dcd7313e4>
- <https://git.kernel.org/stable/c/be15b8da4a82cf1e1f9880b2661b90770606eec1>
- <https://git.kernel.org/stable/c/73f860489e3be2245598d1819226304fc5b87291>

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-2026-89794>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89794/>. Everything for agents: <https://agentprime.io/llms.txt>.