CVE-2021-45444: Apple Mac OS X

High severity, CVSS 7.8. EPSS: 2% chance of exploitation in the next 30 days.

In zsh before 5.8.1, an attacker can achieve code execution if they control a command output inside the prompt, as demonstrated by a %F argument. This occurs because of recursive PROMPT_SUBST expansion.

Affected products

• Apple Mac OS X: from 10.15, before 10.15.7 (fixed in 10.15.7); version 10.15.7 only
• Apple macOS: from 11.0, before 11.6.6 (fixed in 11.6.6); from 12.0.0, before 12.4 (fixed in 12.4)
• Debian Debian Linux: version 9.0 only; version 10.0 only; version 11.0 only
• Fedoraproject Fedora: version 34 only; version 35 only
• Zsh Zsh: before 5.8.1 (fixed in 5.8.1)

Published 2022-02-14. Last modified 2026-06-17.