prefs.php in phpBB 1.4.0 and earlier allows remote authenticated users to execute arbitrary PHP code via an invalid language value, which prevents the variables (1) $l_statsblock in prefs.php or (2) $l_privnotify in auth.php from being properly initialized, which can be modified by the user and later used in an eval statement.
Severity
CVSS 3.1
8.8 high
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
7.7% chance of exploitation in the next 30 days; higher than 94% of CVEs (scores of 2026-10-31)