CVE-2024-39292: um: Add winch to winch_handlers before registering winch IRQ

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-24 · updated 2026-10-15
Weakness: CWE-415

Description

In the Linux kernel, the following vulnerability has been resolved: um: Add winch to winch_handlers before registering winch IRQ Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winch_handlers list. If that happens, register_winch_irq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winch_cleanup(). Avoid the race by adding the winch to the winch_handlers list before registering the IRQ, and rolling back if um_request_irq() fails.

Affected products

Linux kernel: before 2.6.23; from 4.19 before 4.19.316; from 5.4 before 5.4.278; from 5.10 before 5.10.219; from 5.15 before 5.15.161; from 6.1 before 6.1.93 — fixed in 2.6.23, 4.19.316, 5.10.219, 5.15.161, 5.4.278, 6.1.93

How to fix

Upgrade to a fixed version: Linux kernel 2.6.23, 4.19.316, 5.10.219, 5.15.161. Check the vendor advisory for mitigations.

References

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