CVE-2021-47650: ASoC: soc-compress: prevent the potentially use of null pointer

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: ASoC: soc-compress: prevent the potentially use of null pointer There is one call trace that snd_soc_register_card() ->snd_soc_bind_card()->soc_init_pcm_runtime() ->snd_soc_dai_compress_new()->snd_soc_new_compress(). In the trace the 'codec_dai' transfers from card->dai_link, and we can see from the snd_soc_add_pcm_runtime() in snd_soc_bind_card() that, if value of card->dai_link->num_codecs is 0, then 'codec_dai' could be null pointer caused by index out of bound in 'asoc_rtd_to_codec(rtd, 0)'. And snd_soc_register_card() is called by various platforms. Therefore, it is better to add the check in the case of misusing. And because 'cpu_dai' has already checked in soc_init_pcm_runtime(), there is no need to check again. Adding the check as follow, then if 'codec_dai' is null, snd_soc_new_compress() will not pass through the check 'if (playback + capture != 1)', avoiding the leftover use of 'codec_dai'.

Affected products

Linux kernel: from 5.4 before 5.4.189; from 5.5 before 5.10.110; from 5.11 before 5.15.33; from 5.16 before 5.16.19; from 5.17 before 5.17.2 — fixed in 5.10.110, 5.15.33, 5.16.19, 5.17.2, 5.4.189

How to fix

Upgrade to a fixed version: Linux kernel 5.10.110, 5.15.33, 5.16.19, 5.17.2. Check the vendor advisory for mitigations.

References

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