CVE-2026-91955
Description
A flaw was found in FreeRDP. FreeRDP contains a flaw where it fails to validate client-supplied desktop dimensions during the Graphics Command Channel (GCC) negotiation. A remote attacker can exploit this by sending crafted Remote Desktop Protocol (RDP) packets with zero or oversized dimensions. This can lead to division-by-zero or assertion failures, causing the server process to terminate and resulting in a denial of service.
Mitigation
To reduce exposure, restrict network access to the FreeRDP server to trusted clients only. Configure firewall rules to limit incoming connections to the RDP port (typically 3389) from known and authorized IP addresses or subnets. If the FreeRDP server is not essential, consider disabling the service to prevent exploitation. Any changes to firewall rules or service status may require a service restart 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 | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
A Divide by Zero results in a crash.
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