The MISP installer scripts (for Debian 12, Debian 13, Ubuntu 24.04, and RHEL 9.4) create a log file at /var/log/misp_install.log and a named pipe (FIFO) at /var/log/misp_install.log.pipe to capture all installer output. The log captures highly sensitive data including the generated admin password, database passwords, GPG passphrase, and supervisor password. However, the log file was created by the tee command under the system default umask, resulting in world-readable permissions (typically 0644). Similarly, the FIFO was created with mkfifo without an explicit mode, also inheriting the default umask and remaining world-readable during the window before it was unlinked.  Any local unprivileged user on the system could read the log file or the FIFO to obtain these credentials.  Additionally, the log file was not removed before creation, meaning a pre-existing symlink in /var/log could have been used to redirect the write to an arbitrary location. Version affected: <2.5.47