ZoneMinder is a free, open source closed-circuit television software application. Prior to 1.38.3, downloadEvents() manually wraps a monitor Name value in single quotes instead of using escapeshellarg() before placing it in shell commands when a user with monitor-create or monitor-edit permission stores a monitor Name containing shell metacharacters and a user with Events View permission exports that monitor's events. In this attack mechanism, the stored monitor Name reaches both the ffmpeg concatenation command and the tar or zip archive command and breaks out of manual quoting. Arbitrary commands execute as the web server user. This issue is fixed in version 1.38.3.
https://www.scriptkittens.com/blog/two-sinks-one-shell
https://github.com/ZoneMinder/zoneminder/security/advisories/GHSA-88m4-hrgp-m9v3
https://github.com/ZoneMinder/zoneminder/releases/tag/1.38.3
https://github.com/ZoneMinder/zoneminder/commit/b5605e01c14354fc8e2dcae8cefd90c3674880d9
https://github.com/ZoneMinder/zoneminder/commit/b3a7c05f079c87badf4b0ce052da0acfd4047a4b
https://github.com/ZoneMinder/zoneminder/commit/2de2ae44a1d751bad4b020c5573b2d58c59c1525