CVE-2019-12525: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 24.4% chance of exploitation in the next 30 days.

An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1.

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 16.04 only; version 18.04 only; version 19.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 29 only
• Opensuse Leap: version 15.0 only; version 15.1 only
• Squid-Cache Squid: from 3.3.9, up to and including 3.5.28; from 4.0, up to and including 4.7

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