CVE-2021-3497

Vulnerability

A use-after-free vulnerability exists in the Matroska demuxer of GStreamer's gst-plugins-good package before version 1.18.4 [3]. The flaw occurs in error code paths when processing specially crafted Matroska files, causing the application to access already-freed memory [2]. Affected versions include gst-plugins-good 1.x up to 1.18.3 and 0.10.x after 0.10.8 [3].

Exploitation

An attacker can exploit this vulnerability by providing a malformed Matroska (.mkv) file to a target user, who must open it with an application using GStreamer [3]. The malicious file triggers an error during demuxing, leading to a use-after-free condition [2]. No authentication or special network position is required; the attack vector is local file processing or potentially network streams.

Impact

Successful exploitation could cause a denial of service (application crash) or, as the analysis indicates, possibly arbitrary code execution with the privileges of the user running the application [2][3]. Code execution is described as difficult due to modern compiler and glibc protections, but the risk remains [2].

Mitigation

The vulnerability is fixed in gst-plugins-good version 1.18.4 and later [3]. Gentoo users should update to >=media-libs/gst-plugins-good-1.20.2 [1]. No known workaround exists [1]. Users are advised to upgrade as soon as possible.