ksmbd: use opener credentials for ADS I/O
CVE-2026-64391 · published 25 Jul 2026
How serious is it
- Severity: critical, CVSS score 9.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-64391?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: f44158485826c076335d6860d35872271a83791d to < 2ad5509dd576ae16d252d4698daf03002f9e0234, f44158485826c076335d6860d35872271a83791d to < a8f5d39971bbad9340d49cd41b0e2da9452a649d, f44158485826c076335d6860d35872271a83791d to < 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab, f44158485826c076335d6860d35872271a83791d to < 52a56cf53ec834c44ac1b4d16d585f26613ee5ce
- Linux Linux: 5.15
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for ADS I/O
Alternate data streams are stored as xattrs. Unlike regular file I/O,
their read and write paths therefore call VFS xattr helpers which recheck
inode permissions and LSM policy using the current task credentials.
Run ADS I/O with the credentials captured when the SMB handle was opened.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/2ad5509dd576ae16d252d4698daf03002f9e0234
- git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d
- git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab
- git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce
- git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON