su-exec through 0.3 fails to validate numeric user and group identifiers parsed with strtol before assigning to uid_t and gid_t, allowing truncation of out-of-range values to zero. Attackers can supply large numeric identifiers that truncate to root's identifier, causing su-exec to execute target programs with root privileges instead of intended unprivileged accounts.

su-exec through 0.3 fails to validate numeric user and group identifiers parsed with strtol before assigning to uid_t and gid_t, allowing truncation of out-of-range values to zero. Attackers can supply large numeric identifiers that truncate to root's identifier, causing su-exec to execute target programs with root privileges instead of intended unprivileged accounts.