CVE-2025-39822 io_uring/kbuf: fix signedness in this_len calculation
A signedness error in Linux kernel io_uring buffer handling can cause unexpected behavior with large buffers, requiring a kernel patch.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39822?
CVE-2025-39822 is a medium-severity vulnerability in Linux kernel, published on 16 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
io_uring/kbuf: fix signedness in this_len calculation
When importing and using buffers, buf->len is considered unsigned. However, buf->len is converted to signed int when committing. This can lead to unexpected behavior if the buffer is large enough to be interpreted as a negative value. Make min_t calculation unsigned.
Which versions are affected by CVE-2025-39822?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39822?
Apply the vendor's patch.
Is CVE-2025-39822 being exploited?
There is no known exploitation of CVE-2025-39822 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-39822, DEBIAN-CVE-2025-39822, GHSA-5xmf-424g-jjhg, ROOT-OS-DEBIAN-13-CVE-2025-39822, UBUNTU-CVE-2025-39822.