CVE-2026-43185
Heap Buffer Overflow in Linux Kernel ksmbd
Publication date: 2026-05-06
Last updated on: 2026-05-11
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | From 6.19 (inc) to 6.19.6 (exc) |
| linux | linux_kernel | From 5.15 (inc) to 6.18.16 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-674 | The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Linux kernel's ksmbd component, specifically in the smb_direct_prepare_negotiation() function. The issue arises because the function casts unsigned 32-bit values to signed integers before comparing them, which leads to incorrect comparisons when a maliciously crafted preferred_send_size value of 0x80000000 is used.
Due to this incorrect casting, the function incorrectly determines the minimum size, allowing an attacker to set a maximum allowed receive size that is too large. By sending a second message with a size greater than 1420 bytes, the attacker can trigger a heap buffer overflow.
The vulnerability was fixed by replacing the signed integer comparison with an unsigned 32-bit comparison to correctly handle the values.
How can this vulnerability impact me? :
This vulnerability can allow an attacker to cause a heap buffer overflow in the Linux kernel's ksmbd service. A heap buffer overflow can lead to memory corruption, which may be exploited to execute arbitrary code, cause a denial of service (system crash), or escalate privileges on the affected system.