CVE-2026-64257
Linux Kernel vulnerability
- Published25 Jul 2026
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HAffected products
Remediation
- 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
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
Is CVE-2026-64257 being actively exploited?
CVE-2026-64257 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.70%.
How severe is CVE-2026-64257?
CVE-2026-64257 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.70% probability of exploitation.
Which products are affected by CVE-2026-64257?
Affected products include Linux Kernel.
How do I fix CVE-2026-64257?
Upgrade affected software to a fixed version, for example Linux Kernel 5.11 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-64257 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.