CVE-2026-43185
ksmbd: fix signededness bug in smb_direct_prepare_negotiation()
- State
- Published
- Severity
- 9.8 Critical
- Published
- May 6, 2026
- Updated
- Oct 30, 2026
- Reserved
- May 1, 2026
Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix signededness bug in smb_direct_prepare_negotiation()
smb_direct_prepare_negotiation() casts an unsigned __u32 value from sp->max_recv_size and req->preferred_send_size to a signed int before computing min_t(int, ...). A maliciously provided preferred_send_size of 0x80000000 will return as smaller than max_recv_size, and then be used to set the maximum allowed alowed receive size for the next message.
By sending a second message with a large value (>1420 bytes) the attacker can then achieve a heap buffer overflow.
This fix replaces min_t(int, ...) with min_t(u32)
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | Linux |
Weaknesses
The record names no weakness.
Affected Products
| Product | Versions |
|---|---|
LinuxLinux |
|
LinuxLinux |
|
References
- https://git.kernel.org/stable/c/1c268fd2f59dc9ccb2c2a7d1f439b232dbe1c06c
- https://git.kernel.org/stable/c/56eab82fa6fb5ca024b0514e249d40d9b23ee5a7
- https://git.kernel.org/stable/c/a110dbe928561d440e9e117d17331139a0bedace
- https://git.kernel.org/stable/c/ceae058eb707ddd0d68f0872f9d9f23b7c30c37b
- https://git.kernel.org/stable/c/55abc475d096da4a5356b6efb0cfdc6156bc1550
- https://git.kernel.org/stable/c/6b4f875aac344cdd52a1f34cc70ed2f874a65757
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