CVE-2018-13259: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 2.7% chance of exploitation in the next 30 days.

An issue was discovered in zsh before 5.6. Shebang lines exceeding 64 characters were truncated, potentially leading to an execve call to a program name that is a substring of the intended one.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Zsh Zsh: before 5.6 (fixed in 5.6)

Published 2018-09-05. Last modified 2026-06-17.