CVE-2025-39685: comedi: pcl726: Prevent invalid irq number

Vulnerability summary

CVE-2025-39685 is a high (CVSS 7.1) Out-of-bounds Read vulnerability in debian debian_linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.7% of scored vulnerabilities.

Timeline

1. 05-09-2025
   PublishedVulnerability first disclosed.
2. 12-05-2026
   Last modifiedVulnerability information updated.

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.