CVE-2026-64257
Published: July 29, 2026Last modified: July 29, 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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.1 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-r0) |
| 25 LTS | linux-lts | Not affected (6.6.89-r0) | |
| Stream | linux-lts | Not affected (6.1.33-r0) |
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