CVE-2025-68237 mtdchar: fix integer overflow in read/write ioctls
A local attacker can trigger an integer overflow in Linux kernel MTD character device ioctls, potentially causing a denial of service or arbitrary code execution.
- 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-2025-68237?
CVE-2025-68237 is a vulnerability in Linux, published on 16 Dec 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:
mtdchar: fix integer overflow in read/write ioctls
The "req.start" and "req.len" variables are u64 values that come from the user at the start of the function. We mask away the high 32 bits of "req.len" so that's capped at U32_MAX but the "req.start" variable can go up to U64_MAX which means that the addition can still integer overflow.
Use check_add_overflow() to fix this bug.
Which versions are affected by CVE-2025-68237?
How do I fix CVE-2025-68237?
Apply the vendor's patch.
Is CVE-2025-68237 being exploited?
There is no known exploitation of CVE-2025-68237 in the wild and no public exploit code.
Sources
Also known as AZL-72520, BELL-CVE-2025-68237, DEBIAN-CVE-2025-68237, GHSA-q3xh-v3rf-7vqm, ROOT-OS-UBUNTU-2404-CVE-2025-68237, UBUNTU-CVE-2025-68237.