CVE-2021-47511: ALSA: pcm: oss: Fix negative period/buffer sizes

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: 2024-05-24 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: oss: Fix negative period/buffer sizes The period size calculation in OSS layer may receive a negative value as an error, but the code there assumes only the positive values and handle them with size_t. Due to that, a too big value may be passed to the lower layers. This patch changes the code to handle with ssize_t and adds the proper error checks appropriately.

Affected products

Linux kernel: before 4.4.295; from 4.5 before 4.9.293; from 4.10 before 4.14.258; from 4.15 before 4.19.221; from 4.20 before 5.4.165; from 5.5 before 5.10.85 — fixed in 4.14.258, 4.19.221, 4.4.295, 4.9.293, 5.10.85, 5.15.8

How to fix

Upgrade to a fixed version: Linux kernel 4.14.258, 4.19.221, 4.4.295, 4.9.293. Check the vendor advisory for mitigations.

References

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