CVE-2026-64391
Published Jul 25, 2026
Description
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.
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EPSS — Exploit Prediction
0.0021
Probability of exploitation
0.11%
Percentile rank
EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.
References
Other References
Frequently Asked Questions
What is CVE-2026-64391? +
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.
How do I check if I'm vulnerable to CVE-2026-64391? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.