HOMEVULNERABILITIESCVE-2021-38171
CRITICAL

CVE-2021-38171

CWE-252Published: August 21, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

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.

NVD Source

Technical Analysis

CVE-2021-38171 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
ffmpeg1 product(s)
ffmpeg
Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/FFmpeg/FFmpeg/commit/9ffa49496d1aae4cbbb387aac28a9e061a6ab0a6
PATCHhttps://github.com/FFmpeg/FFmpeg/commit/9ffa49496d1aae4cbbb387aac28a9e061a6ab0a6
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/11/msg00012.html
ADVISORYhttps://www.debian.org/security/2021/dsa-4990
ADVISORYhttps://www.debian.org/security/2021/dsa-4998
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/11/msg00012.html
ADVISORYhttps://www.debian.org/security/2021/dsa-4990
ADVISORYhttps://www.debian.org/security/2021/dsa-4998

All References (12)

→
https://github.com/FFmpeg/FFmpeg/commit/9ffa49496d1aae4cbbb387aac28a9e061a6ab0a6Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/11/msg00012.htmlMailing List · Third Party Advisory
→
https://patchwork.ffmpeg.org/project/ffmpeg/patch/AS8P193MB12542A86E22F8207EC971930B6F19%40AS8P193MB1254.EURP193.PROD.OUTLOOK.COM/
→
https://security.gentoo.org/glsa/202312-14
→
https://www.debian.org/security/2021/dsa-4990Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4998Third Party Advisory
→
https://github.com/FFmpeg/FFmpeg/commit/9ffa49496d1aae4cbbb387aac28a9e061a6ab0a6Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/11/msg00012.htmlMailing List · Third Party Advisory
→
https://patchwork.ffmpeg.org/project/ffmpeg/patch/AS8P193MB12542A86E22F8207EC971930B6F19%40AS8P193MB1254.EURP193.PROD.OUTLOOK.COM/
→
https://security.gentoo.org/glsa/202312-14
→
https://www.debian.org/security/2021/dsa-4990Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4998Third Party Advisory

Quick Facts

CVE IDCVE-2021-38171
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-252
CISA KEVNo
Affected2 vendor(s)
PublishedAug 21, 2021

Related CVEs (CWE-252)

CVE-2007-3798
9.8
CVE-2022-25718
9.8
CVE-2019-15900
9.8
CVE-2021-26955
9.8
CVE-1999-0199
9.8
CVE-2010-0211
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-38171 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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