CVE-2019-12527

A flaw was discovered in Squid versions 4.0.23 through 4.7. When checking Basic Authentication with HttpHeader::getAuth, Squid uses a global buffer to store the decoded data but does not check that the decoded length is not greater than the buffer. This flaw leads to a heap-based buffer overflow with user-controlled data.

Mitigation

Deny ftp:// protocol URLs being proxied and Cache Manager report access to all clients:

acl FTP proto FTP  
http_access deny FTP  
http_access deny manager