Bug 2467196 (CVE-2026-43185) - CVE-2026-43185 kernel: ksmbd: fix signededness bug in smb_direct_prepare_negotiation()
Summary: CVE-2026-43185 kernel: ksmbd: fix signededness bug in smb_direct_prepare_nego...
Keywords:
Status: NEW
Alias: CVE-2026-43185
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-06 13:10 UTC by OSIDB Bzimport
Modified: 2026-05-06 20:30 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-05-06 13:10:14 UTC
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)


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