CVE-2026-11861
Description
A flaw was found in FreeIPA. When a trust relationship is configured between FreeIPA and Active Directory, Active Directory users can bypass authentication for FreeIPA services, including the portal, SMB server, and LDAP directory. This is possible by impersonating a client name in the Ticket Granting Service (TGS) due to FreeIPA services not verifying Privilege Attribute Certificate (PAC) certificates. This vulnerability could allow an authenticated Active Directory user to escalate their privileges within the FreeIPA domain.
Statement
This vulnerability is rated as Moderate because practical exploitation is significantly constrained by conditions that are unlikely to be met in most production environments. The attack requires a cross-realm trust to be configured between FreeIPA and Active Directory, the attacker must already hold a valid Active Directory account, and the impersonation technique depends on the ability to register a duplicate or conflicting Service Principal Name (SPN) in the Active Directory forest. Microsoft addressed this prerequisite by enforcing SPN and UPN uniqueness constraints on Windows Server 2012 R2 domain controllers with MSKB-3070083 applied, and by default on Windows 11 version 22H2 and later. In environments where the Active Directory domain controllers are patched and running a supported functional level, the attack path is blocked on the Windows side. Only deployments trusting an outdated or unpatched Active Directory environment remain realistically at risk, making this primarily a theoretical concern in modern, maintained environments.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 9.6 | N/A | 9.6 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.
Acknowledgements
Red Hat would like to thank Vladislav Plyatsok (rd01f) for reporting this issue.
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