Decades-Old Squid Proxy Flaw ‘Squidbleed’ Can Expose User Data

Squidbleed, discovered with the aid of Claude Mythos Preview, has been described as a Heartbleed-style vulnerability. The post Decades-Old Squid Proxy Flaw ‘Squidbleed’ Can Expose User Data appeared first on SecurityWeek .

According to SecurityWeek, Squidbleed (CVE-2026-47729) is a decades-old heap over-read vulnerability in Squid’s FTP parser that can leak prior users’ cleartext HTTP request data, including authentication credentials, session tokens, and API keys, to any attacker already allowed to use the same proxy.[1][3][8] The flaw affects long-standing Squid deployments and is likened to Heartbleed because it enables memory disclosure from a widely used infrastructure component rather than direct code execution.[1][3] From a CyberSE.AI perspective, this represents a critical data leakage risk in the AI supply chain: organizations may have Squid embedded in appliances or in front of AI services and APIs, so unpatched proxies can silently expose model API keys, user tokens, and sensitive request payloads transiting to AI systems. Practically, security teams should inventory where Squid is used (including embedded products), rapidly apply or verify patches, disable FTP support where possible, and include Squid and similar proxy components in SBOM-driven AI supply chain risk management and continuous monitoring.