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Uncontrolled Resource Consumption in path-to-regexp

CVE-2026-4926

  • path-to-regexp
High
7.5/10

Summary

A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as "{a}{b}{c}:z". The generated regex grows exponentially with the number of groups, causing denial of service. Fixed in version 8.4.0.

  • LOW
  • NETWORK
  • NONE
  • UNCHANGED
  • NONE
  • NONE
  • NONE
  • HIGH

CWE-400 - Uncontrolled resource consumption

An uncontrolled resource allocation attack (also known as resource exhaustion attack) triggers unauthorized overconsumption of the limited resources in an application, such as memory, file system storage, database connection pool entries, and CPU. This may lead to denial of service for valid users and degradation of the application's functionality as well as that of the host operating system.

References

Advisory Timeline

  • Published