CVE-2025-39713 media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()
A race condition in the rainshadow-cec driver allows buffer overflow, potentially leading to code execution or 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-2025-39713?
CVE-2025-39713 is a medium-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:
media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()
In the interrupt handler rain_interrupt(), the buffer full check on rain->buf_len is performed before acquiring rain->buf_lock. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as rain->buf_len is concurrently accessed and modified in the work handler rain_irq_work_handler() under the same lock.
Multiple interrupt invocations can race, with each reading buf_len before it becomes full and then proceeding. This can lead to both interrupts attempting to write to the buffer, incrementing buf_len beyond its capacity (DATA_SIZE) and causing a buffer overflow.
Fix this bug by moving the spin_lock() to before the buffer full check. This ensures that the check and the subsequent buffer modification are performed atomically, preventing the race condition. An corresponding spin_unlock() is added to the overflow path to correctly release the lock.
This possible bug was found by an experimental static analysis tool developed by our team.
Weakness: CWE-367
Which versions are affected by CVE-2025-39713?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39713?
Apply the vendor's patch.
Is CVE-2025-39713 being exploited?
There is no known exploitation of CVE-2025-39713 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-39713, DEBIAN-CVE-2025-39713, GHSA-pf4v-7q2j-5rw9, ROOT-OS-DEBIAN-11-CVE-2025-39713, ROOT-OS-DEBIAN-12-CVE-2025-39713, ROOT-OS-DEBIAN-13-CVE-2025-39713 and 3 more.