CVE-2026-72746
Description
A flaw was found in FreeRDP. An unauthenticated remote attacker could bypass the server-side authentication in the RDSTLS (Remote Desktop Services Transport Layer Security) handshake. By sending a Capabilities PDU instead of the expected Authentication Request PDU, the server incorrectly processes the request, leading to a successful authentication without validating any credentials. This allows the attacker to gain unauthorized access to a session.
Statement
This is an Important flaw where FreeRDP servers configured with RDSTLS security are vulnerable to an authentication bypass. An unauthenticated remote attacker can exploit a PDU-type confusion during the handshake to gain unauthorized access, circumventing credential checks. This poses a significant risk to the confidentiality of systems exposing FreeRDP with RDSTLS enabled.
Mitigation
To mitigate this issue, ensure that FreeRDP servers are not configured with `RdstlsSecurity = TRUE` unless explicitly required. If `RdstlsSecurity` is necessary, restrict network access to the FreeRDP server to trusted clients only, for example, by implementing firewall rules. Restarting the FreeRDP server may be required for configuration changes to take effect.
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 | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
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