A vulnerability was found in sssd. If a user was configured with no home directory set, sssd would return '/' (the root directory) instead of '' (the empty string / no home directory). This could impact services that restrict the user's filesystem access to within their home directory through chroot() etc. All versions before 2.1 are vulnerable.
sssd versions from 1.13.0 to before 2.0.0 did not properly restrict access to the infopipe according to the "allowed_uids" configuration parameter. If sensitive information were stored in the user directory, this could be inadvertently disclosed to local attackers.
It was found that sssd's sysdb_search_user_by_upn_res() function before 1.16.0 did not sanitize requests when querying its local cache and was vulnerable to injection. In a centralized login environment, if a password hash was locally cached for a given user, an authenticated attacker could use this flaw to retrieve it.
The UNIX pipe which sudo uses to contact SSSD and read the available sudo rules from SSSD has too wide permissions, which means that anyone who can send a message using the same raw protocol that sudo and SSSD use can read the sudo rules available for any user. This affects versions of SSSD before 1.16.3.