Heap-based Buffer Overflow in Squid Caching Proxy

CVE-2026-50012

What is CVE-2026-50012?

The Squid caching proxy is susceptible to a heap-based buffer overflow due to improper input validation in its cache digest reply handling. When exploitatively manipulated, a cache digest's size on the wire can exceed the expected mask size indicated within the digest. This vulnerability specifically impacts Squid instances compiled with the --enable-cache-digests option and those that have configured entries for cache peers. Attackers could exploit this flaw by sending a malicious reply to a cache_digest request, leading to potential disruption or unauthorized access. This issue has been resolved in version 7.6.

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