Critical severity · published Jul 25, 2026
CVE-2026-64257
smb: client: reject overlapping data areas in SMB2 responses
9.1
CVSS
0.7%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.10.261 before 5.11; 5.15.212 before 5.16; 7.2 · source: NVD
LI
Linux · Linux
31c6312608c60b72a1feb99a5afb680645a3e8a3 before 445ece263131780dee273d727a4d6f11934feec7; 573e502d14714d2947e22e7eff40ec20a6a44a42 before 36bfa52459e45c0d5b668de2f1c91f6dc5c67775; 419ec1b604d7fb60c10aec2dc062371f9fcd4940 before 4a9d2657d3e05f6ed09c148cb127b4e58702275f; ceb875a375dedbf51c9425c1d13a2d7a8435c08c before fdafa1e68dc75045b7b617e6e7d2854950804d83; 6e9d10f62773b99bd927940fd9cbdfe7207e23ff before 57cba95f0e97c6f6e45e6731da30aff091bd7460; 53b7c271f06be4dd5cfc8c6ef552a8355c891a7f before 8986c932905ea508d66da421eb2eb6e676ace1fe; +4 more · source: vendor