# ksmbd: preserve VFS inherited POSIX ACL mask

CVE record · `CVE-2026-93786`

- **Identifiers:** `CVE-2026-93786`
- **State:** Confirmed
- **Severity:** CVSS 8.1 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 24 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 24 Sept 2026, 16:02 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: `f44158485826c076335d6860d35872271a83791d to before 8493da704275ca5ab67fb88c0ae7b71576e91951` (git)
  - affected: `f44158485826c076335d6860d35872271a83791d to before 4a19bb1c45667f5a5f6eff9cf6648e0f692d046f` (git)
  - affected: `f44158485826c076335d6860d35872271a83791d to before 591acf171644de590cda245fd8595b473a1beb70` (git)
  - affected: `f44158485826c076335d6860d35872271a83791d to before 0093909becbda22b62b39b654dbc607faed59cd0` (git)
  - affected: `f44158485826c076335d6860d35872271a83791d to before e148e567a9252643baa125cb65d7ae9c2c6cf68a` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.15`
  - unaffected: `before 5.15` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.158 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.111 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.53 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2 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 ksmbd SMB server, from 5.15 before the fixes, can widen effective permissions on objects created over SMB beyond what restrictive POSIX ACL mask entries allow. The source gives few details on what access an attacker needs. Upgrade to 6.1.191, 6.6.158, 6.12.111, 6.18.53, or a later release in those series.

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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0034, the 28th percentile, on 13 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 24 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-93786](https://www.cve.org/CVERecord?id=CVE-2026-93786)
- [NVD: CVE-2026-93786](https://nvd.nist.gov/vuln/detail/CVE-2026-93786)

### References from the CNA

- <https://git.kernel.org/stable/c/8493da704275ca5ab67fb88c0ae7b71576e91951>
- <https://git.kernel.org/stable/c/4a19bb1c45667f5a5f6eff9cf6648e0f692d046f>
- <https://git.kernel.org/stable/c/591acf171644de590cda245fd8595b473a1beb70>
- <https://git.kernel.org/stable/c/0093909becbda22b62b39b654dbc607faed59cd0>
- <https://git.kernel.org/stable/c/e148e567a9252643baa125cb65d7ae9c2c6cf68a>

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-2026-93786>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-93786/>. Everything for agents: <https://agentprime.io/llms.txt>.