CVE-2026-121950
Description
A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can cause a denial of service (DoS) or memory corruption on a connecting client. This issue occurs because FreeRDP does not properly validate graphical surface dimensions, resulting in an integer overflow during memory allocation calculations. By sending a specially crafted surface creation message, a rogue server can trigger excessive memory consumption or a heap-based buffer overflow, causing the client application to crash.
Statement
This vulnerability is evaluated as Moderate impact for Red Hat products because exploitation requires client-side user interaction to connect to an untrusted remote system, restricting the potential blast radius to the local application session. On standard 64-bit Red Hat Enterprise Linux architectures, the arithmetic wrap does not occur; instead, the oversized dimension request triggers an excessively large memory allocation that terminates the client process rather than corrupting memory. As a result, an attacker is limited to causing a denial of service on the client without compromising host system integrity or achieving arbitrary code execution.
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 | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| 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:R/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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