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 flaw was found in ksmbd within the Linux kernel. A remote attacker can exploit a signedness bug in the smb_direct_prepare_negotiation() function by sending a specially crafted preferred_send_size value during SMB direct negotiation. This manipulation leads to an incorrect size calculation, allowing a subsequent large message to trigger a heap buffer overflow. A successful exploit could result in arbitrary code execution or a denial of service.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-43185 https://nvd.nist.gov/vuln/detail/CVE-2026-43185 https://lore.kernel.org/linux-cve-announce/2026050640-CVE-2026-43185-55a5@gregkh/T