➠ Nextcloud: [nextcloud/server] Moment.js vulnerable to Inefficient Regular Expression Complexity

Describe the bugs: 🐛 moment is a lightweight JavaScript date library for parsing, validating, manipulating, and formatting dates. affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the preprocessRFC2822() function in from-string.js, when processing a very long crafted string (over 10k characters). PoC: javascript moment("(".repeat(500000)) Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process. The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down. Let’s take the following regular expression as an: javascript regex = /A(B|C+)+D/ This regular expression accomplishes the following: * A The string must start with the letter 'A' * (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one......