CVE-2026-91142

A flaw was found in Cockpit. An integer overflow vulnerability in the do_lastlog() function, specifically in the offset calculation for lastlog entries on ILP32 (Integer, Long, Pointer 32-bit) builds, can be exploited. A low-privileged authenticated user with a specially provisioned large User ID (UID) can cause the computed offset to wrap around. This allows the user to perform unauthorized reads and writes to other users' lastlog records, potentially disclosing or altering sensitive login accounting information.