CVE-2026-43185
ksmbd: fix signededness bug in smb_direct_prepare_negotiation()
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)
INFO
Published Date :
May 6, 2026, 12:16 p.m.
Last Modified :
May 11, 2026, 8:52 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Apply the kernel patch to fix signedness bug.
- Replace min_t(int, ...) with min_t(u32).
- Update the Linux kernel.
References to Advisories, Solutions, and Tools
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CVE-2026-43185.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43185 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43185
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-43185 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-43185 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
May. 11, 2026
Action Type Old Value New Value Added CWE CWE-674 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 6.19.6 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.15 up to (excluding) 6.18.16 Added Reference Type kernel.org: https://git.kernel.org/stable/c/55abc475d096da4a5356b6efb0cfdc6156bc1550 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/6b4f875aac344cdd52a1f34cc70ed2f874a65757 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/ceae058eb707ddd0d68f0872f9d9f23b7c30c37b Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 06, 2026
Action Type Old Value New Value Added 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) Added Reference https://git.kernel.org/stable/c/55abc475d096da4a5356b6efb0cfdc6156bc1550 Added Reference https://git.kernel.org/stable/c/6b4f875aac344cdd52a1f34cc70ed2f874a65757 Added Reference https://git.kernel.org/stable/c/ceae058eb707ddd0d68f0872f9d9f23b7c30c37b