CVE-2026-43185 Details
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)
A heap buffer overflow vulnerability has been identified in the Linux kernel's ksmbd component. This issue arises from a signedness bug in the 'smb_direct_prepare_negotiation()' function, which improperly casts an unsigned __u32 value from 'max_recv_size' and 'preferred_send_size' to a signed integer. An attacker can exploit this by sending a crafted 'preferred_send_size' value, causing the function to misinterpret the maximum receive size. This manipulation allows the attacker to set an artificially low receive size, which can be bypassed in subsequent messages, leading to a buffer overflow.
Users can upgrade to the patched version of the Linux kernel available in the official Linux Git repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/55abc475d096da4a5356b6efb0cfdc6156bc1550 | kernel.org | Patch |
| https://git.kernel.org/stable/c/6b4f875aac344cdd52a1f34cc70ed2f874a65757 | kernel.org | Patch |
| https://git.kernel.org/stable/c/ceae058eb707ddd0d68f0872f9d9f23b7c30c37b | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-674 | Uncontrolled Recursion | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.15, < 6.18.16 >= 6.19, < 6.19.6 7.0 rc1 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 11, 2026 | Initial Analysis | [email protected] |
| May 8, 2026 | CVE Modified | kernel.org |
| May 6, 2026 | New CVE Received | kernel.org |