CVE-2026-64257

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions.

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EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.12%

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

https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775 https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7 https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460 https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83

Frequently Asked Questions

What is CVE-2026-64257? +

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions.

How do I check if I'm vulnerable to CVE-2026-64257? +

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.