CVE-2026-43185

CRITICAL

ksmbd: fix signededness bug in smb_direct_prepare_negotiation()

Title source: cna
STIX 2.1

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 v3 9.8
EPSS 0.0062
EPSS Percentile 45.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-674
Status published
Products (12)
linux/Kernel 5.15.0 - 6.18.16linux
linux/Kernel 6.19.0 - 6.19.6linux
Linux/Linux < 5.15
Linux/Linux 0626e6641f6b467447c81dd7678a69c66f7746cf - 55abc475d096da4a5356b6efb0cfdc6156bc1550
Linux/Linux 0626e6641f6b467447c81dd7678a69c66f7746cf - 6b4f875aac344cdd52a1f34cc70ed2f874a65757
Linux/Linux 0626e6641f6b467447c81dd7678a69c66f7746cf - ceae058eb707ddd0d68f0872f9d9f23b7c30c37b
Linux/Linux 5.15
Linux/Linux 6.18.16 - 6.18.*
Linux/Linux 6.19.6 - 6.19.*
Linux/Linux 7.0
... and 2 more
Published May 06, 2026
Tracked Since May 06, 2026