CVE-2025-39685 comedi: pcl726: Prevent invalid irq number
A local attacker can trigger an out-of-bounds access in the pcl726 driver by passing an invalid IRQ number, causing a denial of service.
- 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-2025-39685?
CVE-2025-39685 is a high-severity vulnerability in Debian Debian Linux, published on 5 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:
comedi: pcl726: Prevent invalid irq number
The reproducer passed in an irq number(0x80008000) that was too large, which triggered the oob.
Added an interrupt number check to prevent users from passing in an irq number that was too large.
If `it->options[1]` is 31, then `1 << it->options[1]` is still invalid because it shifts a 1-bit into the sign bit (which is UB in C). Possible solutions include reducing the upper bound on the `it->options[1]` value to 30 or lower, or using `1U << it->options[1]`.
The old code would just not attempt to request the IRQ if the `options[1]` value were invalid. And it would still configure the device without interrupts even if the call to `request_irq` returned an error. So it would be better to combine this test with the test below.
Weakness: CWE-125
Which versions are affected by CVE-2025-39685?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39685?
Apply the vendor's patch.
Is CVE-2025-39685 being exploited?
There is no known exploitation of CVE-2025-39685 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-66935, BELL-CVE-2025-39685, DEBIAN-CVE-2025-39685, GHSA-jx84-vrfm-c347, ROOT-OS-DEBIAN-11-CVE-2025-39685, ROOT-OS-DEBIAN-12-CVE-2025-39685 and 4 more.