apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the explicit SocketPath=/var/run/apt-cacher-ng/socket command-line option is passed. The cron job /etc/cron.daily/apt-cacher-ng (which is active by default) attempts this periodically. Because 3142 is an unprivileged port, any local user can try to bind to this port and will receive requests from acngtool. There can be sensitive data in these requests, e.g., if AdminAuth is enabled in /etc/apt-cacher-ng/security.conf. This sensitive data can leak to unprivileged local users that manage to bind to this port before the apt-cacher-ng daemon can.

The apt-cacher-ng package of openSUSE Leap 15.1 runs operations in user owned directory /run/apt-cacher-ng with root privileges. This can allow local attackers to influence the outcome of these operations. This issue affects: openSUSE Leap 15.1 apt-cacher-ng versions prior to 3.1-lp151.3.3.1.

apt-cacher before 1.7.15 and apt-cacher-ng before 3.4 allow HTTP response splitting via encoded newline characters, related to lack of blocking for the %0[ad] regular expression.