CVE-2019-12527: Canonical Ubuntu Linux

High severity, CVSS 8.8. EPSS: 49% chance of exploitation in the next 30 days.

An issue was discovered in Squid 4.0.23 through 4.7. When checking Basic Authentication with HttpHeader::getAuth, Squid uses a global buffer to store the decoded data. Squid does not check that the decoded length isn't greater than the buffer, leading to a heap-based buffer overflow with user controlled data.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.04 only
• Debian Debian Linux: version 10.0 only
• Fedoraproject Fedora: version 29 only
• Red Hat Enterprise Linux: version 8.0 only
• Red Hat Enterprise Linux Eus: version 8.1 only; version 8.2 only; version 8.4 only; version 8.6 only
• Red Hat Enterprise Linux Server Aus: version 8.2 only; version 8.4 only; version 8.6 only
• Red Hat Enterprise Linux Server Tus: version 8.2 only; version 8.4 only; version 8.6 only
• Squid-Cache Squid: from 4.0.23, up to and including 4.7

Published 2019-07-11. Last modified 2026-06-17.