Last Modified: Jul 21, 2026
Affected Product(s):
F5OS F5OS, F5OS-A, F5OS-C
Known Affected Versions:
F5OS-A 1.8.0, F5OS-A 1.8.1, F5OS-A 1.8.2, F5OS-A 1.8.3, F5OS-A 1.8.4
Fixed In:
F5OS v2.0.0
Opened: Aug 01, 2025 Severity: 3-Major
When a TACACS+ server secret contains a newline character, the PAM configuration files (/etc/pam.d/password-auth and /etc/pam.d/system-auth) become corrupted. This causes PAM to report "illegal module type" and "expecting return value" errors, preventing all user authentication, including root login via SSH and console.
TACACS+ authentication to the system is broken.
A TACACS+ server is configured with a secret-key value that contains a literal newline character (U+000A). This can occur either by directly submitting a secret containing a newline via the REST API or when the system's primary key is corrupted, causing the decrypted secret value to contain unexpected characters.
NA
Fixed in F5 v2.0 version.