CVE-2026-104048

A flaw was found in SSSD. In trust-enabled identity management environments, SSSD evaluates Host-Based Access Control (HBAC) rules by stripping domain qualifiers and comparing only short usernames. An authenticated user in a trusted domain who shares the same username as an authorized local account can bypass access policies and gain unauthorized access to protected services or hosts.

This vulnerability is rated as Moderate impact because exploitation requires a non-default trust deployment and an account collision between the local and trusted domains. An authenticated user within a trusted domain can bypass Host-Based Access Control (HBAC) restrictions if their username matches a local Identity Management user explicitly named in an allow rule. The flaw cannot be leveraged remotely by unauthenticated actors, and environments without cross-realm trusts or those utilizing group-based HBAC policies are not exposed.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.