In mistune through 2.0.2, support of inline markup is implemented by using regular expressions that can involve a high amount of backtracking on certain edge cases. This behavior is commonly named catastrophic backtracking.
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 |
|---|---|---|---|
| Mistune | Mistune_project | * | 2.0.2 (including) |
| Mistune | Ubuntu | bionic | * |
| Mistune | Ubuntu | kinetic | * |
| Mistune | Ubuntu | upstream | * |
| Mistune | Ubuntu | xenial | * |
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.