less through 653 allows OS command execution via a newline character in the name of a file, because quoting is mishandled in filename.c. Exploitation typically requires use with attacker-controlled file names, such as the files extracted from an untrusted archive. Exploitation also requires the LESSOPEN environment variable, but this is set by default in many common cases.

https://github.com/gwsw/less/commit/007521ac3c95bc76e3d59c6dbfe75d06c8075c33
https://www.openwall.com/lists/oss-security/2024/04/12/5
https://www.openwall.com/lists/oss-security/2024/04/13/2