In the CGI gem before 0.4.2 for Ruby, a Regular Expression Denial of Service (ReDoS) vulnerability exists in the Util#escapeElement method.
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Cgi | Ruby-lang | * | 0.3.5.1 (excluding) |
| Cgi | Ruby-lang | 0.4.0 (including) | 0.4.2 (excluding) |
| Cgi | Ruby-lang | 0.3.6 (including) | 0.3.6 (including) |
| Ruby3.3 | Ubuntu | devel | * |
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.