29-Year-Old ‘Squidbleed’ Vulnerability Discovered With the Aid of Claude Mythos Preview

Squidbleed is a critical heap-buffer overread in Squid Proxy, present since a 1997 commit, that can read up to ~4KB of adjacent heap memory and leak stale HTTP request data (including Authorization headers and API keys) via a malformed FTP directory listing; the flaw arises from misusing C's strchr on a null terminator, a PoC has been published and a one-line null-check patch has been merged, and administrators are advised to disable FTP proxy support unless required.