CVE-2021-38171 Null dereference in n/a

Critical 9.8 Published 21 Aug 2021 Updated 4 Aug 2024

FFmpeg fails to check the return value of init_get_bits in ADTS decoding, potentially leading to a null pointer dereference and denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2021-38171?

CVE-2021-38171 is a critical vulnerability in Debian Debian Linux, published on 21 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

adts_decode_extradata in libavformat/adtsenc.c in FFmpeg 4.4 does not check the init_get_bits return value, which is a necessary step because the second argument to init_get_bits can be crafted.

Weakness: CWE-252

Which versions are affected by CVE-2021-38171?

It affects 2 products.

Linux distribution packages (17)

`ffmpeg` SUSE:Enterprise Storage 6	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise High Performance Computing 15-ESPOS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise High Performance Computing 15-LTSS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Module for Desktop Applications 15 SP2	All versions	`3.4.2-11.11.1`
`ffmpeg` SUSE:Linux Enterprise Module for Desktop Applications 15 SP3	All versions	`3.4.2-11.11.1`
`ffmpeg` SUSE:Linux Enterprise Module for Package Hub 15 SP2	All versions	`3.4.2-11.11.1`
`ffmpeg` SUSE:Linux Enterprise Module for Package Hub 15 SP3	All versions	`3.4.2-11.11.1`
`ffmpeg` SUSE:Linux Enterprise Server 15 SP1-BCL	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Server 15 SP1-LTSS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Server 15-LTSS	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Server for SAP Applications 15	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Server for SAP Applications 15 SP1	All versions	`3.4.2-4.37.1`
`ffmpeg` SUSE:Linux Enterprise Workstation Extension 15 SP2	All versions	`3.4.2-11.11.1`
`ffmpeg` SUSE:Linux Enterprise Workstation Extension 15 SP3	All versions	`3.4.2-11.11.1`
`ffmpeg` openSUSE:Leap 15.3	All versions	`3.4.2-11.11.1`

Products include Debian Debian Linux, Ffmpeg Ffmpeg.

How do I fix CVE-2021-38171?

Apply the vendor's patch.

Is CVE-2021-38171 being exploited?

There is no known exploitation of CVE-2021-38171 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as CLEANSTART-2024-LF99965, DEBIAN-CVE-2021-38171, GHSA-8cmw-hp26-wrpm, JLSEC-2025-118, SUSE-SU-2021:3193-1, SUSE-SU-2021:3212-1 and 2 more.