Found by CodeQL:

This part of the regular expression may cause exponential backtracking on strings starting with '<!--' and containing many repetitions of '\n'.

Some regular expressions take a long time to match certain input strings to the point where the time it takes to match a string of length n is proportional to nk or even 2n. Such regular expressions can negatively affect performance, or even allow a malicious user to perform a Denial of Service ("DoS") attack by crafting an expensive input string for the regular expression to match.

Tracking issue for:

• https://github.com/certtools/intelmq/security/code-scanning/3