TF2 Item Format helps users format TF2 items to the community standards. Versions of tf2-item-format since at least 4.2.6 and prior to 5.9.14 are vulnerable to a Regular Expression Denial of Service (ReDoS) attack when parsing crafted user input. This vulnerability can be exploited by an attacker to perform DoS attacks on any service that uses any tf2-item-format to parse user input. Version 5.9.14 contains a fix for the issue.
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.
Attackers can create crafted inputs that
intentionally cause the regular expression to use
excessive backtracking in a way that causes the CPU
consumption to spike.