In Ubuntu's accountsservice an unprivileged local attacker can trigger a use-after-free vulnerability in accountsservice by sending a D-Bus message to the accounts-daemon process.

Ubuntu-specific modifications to accountsservice (in patch file debian/patches/0010-set-language.patch) caused the fallback_locale variable, pointing to static storage, to be freed, in the user_change_language_authorized_cb function. This is reachable via the SetLanguage dbus function. This is fixed in versions 0.6.55-0ubuntu12~20.04.5, 0.6.55-0ubuntu13.3, 0.6.55-0ubuntu14.1.

An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.

An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, improperly dropped the ruid, allowing untrusted users to send signals to AccountService, thus stopping it from handling D-Bus messages in a timely fashion.

An issue exists AccountService 0.6.37 in the user_change_password_authorized_cb() function in user.c which could let a local users obtain encrypted passwords.

Directory Traversal with ../ sequences occurs in AccountsService before 0.6.50 because of an insufficient path check in user_change_icon_file_authorized_cb() in user.c.

The Ubuntu AccountsService package before 0.6.14-1git1ubuntu1.1 does not properly drop privileges when changing language settings, which allows local users to modify arbitrary files via unspecified vectors.

The user_change_icon_file_authorized_cb function in /usr/libexec/accounts-daemon in AccountsService before 0.6.22 does not properly check the UID when copying an icon file to the system cache directory, which allows local users to read arbitrary files via a race condition.