CVE-2026-64257
smb: client: reject overlapping data areas in SMB2 responses
- State
- Published
- Severity
- 9.1 Critical
- Published
- Jul 25, 2026
- Updated
- Aug 17, 2026
- Reserved
- Jul 19, 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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H | Linux |
Weaknesses
The record names no weakness.
Affected Products
| Product | Versions |
|---|---|
LinuxLinux |
|
LinuxLinux |
References
- https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7
- https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775
- https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f
- https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83
- https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460
- https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe
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