anchorme through 3.0.8 contains a regular expression denial of service vulnerability in the IPv6 host extraction regex due to catastrophic backtracking. Attackers can supply specially crafted input strings with repeated patterns to cause exponential regex engine backtracking, blocking the Node.js event loop and denying service to other requests.
Weakness
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Potential Mitigations
Related Attack Patterns
References
- https://gist.github.com/mmadersbacher/46050b4224eb979431986cdef1dd2ad3
- https://github.com/alexcorvi/anchorme.js
- https://github.com/alexcorvi/anchorme.js/blob/f3ae9850baa344f27b46bb149e9b891831d273b1/src/index.ts#L109
- https://www.npmjs.com/package/anchorme
- https://www.vulncheck.com/advisories/anchorme-through-3.0.8-regular-expression-denial-of-service
- https://gist.github.com/mmadersbacher/46050b4224eb979431986cdef1dd2ad3