CVE-2024-38618: ALSA: timer: Set lower bound of start tick time

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-19 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Set lower bound of start tick time Currently ALSA timer doesn't have the lower limit of the start tick time, and it allows a very small size, e.g. 1 tick with 1ns resolution for hrtimer. Such a situation may lead to an unexpected RCU stall, where the callback repeatedly queuing the expire update, as reported by fuzzer. This patch introduces a sanity check of the timer start tick time, so that the system returns an error when a too small start size is set. As of this patch, the lower limit is hard-coded to 100us, which is small enough but can still work somehow.

Affected products

Linux kernel: before 4.19.316; from 4.20 before 5.4.278; from 5.5 before 5.10.219; from 5.11 before 5.15.161; from 5.16 before 6.1.93; from 6.2 before 6.6.33 — fixed in 4.19.316, 5.10.219, 5.15.161, 5.4.278, 6.1.93, 6.6.33

How to fix

Upgrade to a fixed version: Linux kernel 4.19.316, 5.10.219, 5.15.161, 5.4.278. Check the vendor advisory for mitigations.

References

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