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Inefficient Regular Expression Complexity


Severity High
Score 7.5/10


Shescape is a shell escape package for JavaScript. An Inefficient Regular Expression Complexity vulnerability impacts users that use Shescape to escape arguments for the Unix shells `Bash` and `Dash`, or any not-officially-supported Unix shell; and/or using the `escape` or `escapeAll` functions with the `interpolation` option set to `true`. An attacker can cause polynomial backtracking or quadratic runtime in terms of the input string length due to two Regular Expressions in Shescape that are vulnerable to Regular Expression Denial of Service (ReDoS). As a workaround, a maximum length can be enforced on input strings to Shescape to reduce the impact of the vulnerability. It is not recommended to try and detect vulnerable input strings, as the logic for this may end up being vulnerable to ReDoS itself. This issue affects versions 1.5.x prior to 1.5.10.

  • LOW
  • NONE
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  • HIGH

CWE-1333 - Inefficient Regular Expression Complexity

The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

Advisory Timeline

  • Published