Collected research

Security: HTTP Smuggling, Apsis Pound load balancer

regilero · regilero.github.io

The Pound load balancer accepts two Content-Length headers, lets whichever framing header came first win over Transfer-Encoding, and treats a NUL byte in a header as a line continuation. Paired with any other HTTP actor that parses differently, one pipelined stream is split into a different number of requests at each hop, giving request smuggling, filter bypass and cache poisoning.

Record

Researcher

regilero

Published by

regilero.github.io

Topic

HTTP

In the archive

• Collected in the 2018 research round

Tags

• request-smuggling
• desync
• parser-differential
• http
• load-balancer
• reverse-proxy
• cache-poisoning
• filter-bypass
• cve
• owasp-a05-2021

This page is the archive's own catalogue record. The research is the work of regilero, 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.