Vulnerability identifier: #VU18321

Vulnerability risk: Low

CVSSv3.1: 3 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-9721

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FFmpeg
Universal components / Libraries / Libraries used by multiple products

Vendor: ffmpeg.sourceforge.net

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input within the subtitle decoder in handle_open_brace() function in libavcodec/htmlsubtitles.c when processing video files in Matroska format. A remote attacker can create a specially crafted video file, pass it to the affected application and consume all available CPU resources.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

FFmpeg: 4.1

---

External links
http://www.securityfocus.com/bid/107384
http://git.ffmpeg.org/gitweb/ffmpeg.git/commit/894995c41e0795c7a44f81adc4838dedc3932e65

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.