CVE-2025-39933 smb: client: let recv_done verify data_offset, data_length and remaining_data_length
A missing validation in the Linux kernel SMB client allows attackers to trigger memory corruption via crafted network packets, potentially leading to code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39933?
CVE-2025-39933 is a critical memory corruption vulnerability in Linux kernel, published on 4 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: let recv_done verify data_offset, data_length and remaining_data_length
This is inspired by the related server fixes.
Which versions are affected by CVE-2025-39933?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39933?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-39933 being exploited?
There is no known exploitation of CVE-2025-39933 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-39933, DEBIAN-CVE-2025-39933, GHSA-2vj6-wmm6-q722, ROOT-OS-DEBIAN-11-CVE-2025-39933, ROOT-OS-DEBIAN-12-CVE-2025-39933, ROOT-OS-DEBIAN-13-CVE-2025-39933 and 3 more.