CVE-2019-12526: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 20.3% chance of exploitation in the next 30 days.

An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.04 only; version 19.10 only
• Debian Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 30 only; version 31 only
• Opensuse Leap: version 15.0 only
• Squid-Cache Squid: from 3.0, up to and including 3.5.28; from 4.0, up to and including 4.8

Published 2019-11-26. Last modified 2026-06-17.