Top 10 winner

Cache Poisoning at Scale

@iustinBB · youst.in

A catalogue of reusable web cache poisoning patterns found across bug bounty targets: Apache Traffic Server forwarding URL fragments it leaves out of the cache key, method-override and scheme headers producing cacheable errors and redirect loops, CDNs caching 403 responses, and host header injection via Fastly-host. They yield denial of service, arbitrary redirects and stored scripting.

Record

Researcher

@iustinBB

Published by

youst.in

Topic

HTTP

In the archive

• Ranked #6 in the 2021 Top 10 Web Hacking Techniques

Related sources

• Earlier research writeup
• Cache-poisoning header corpus

Tags

• cache-poisoning
• dos
• header-injection
• cache
• cdn
• http
• xss
• bug-bounty
• cve
• large-scale-scan
• owasp-a03-2021

This page is the archive's own catalogue record. The research is the work of @iustinBB, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 9 August 2026.