CVE-2026-121954
Description
A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can cause a Denial of Service (DoS) and heap memory corruption on the connecting client. This issue occurs in the planar graphics codec because new display dimensions are applied before memory buffer reallocation succeeds. When reallocation fails, the context is not rolled back, allowing subsequent planar drawing commands to write beyond the allocated buffer boundaries and crash the client.
Statement
Red Hat Product Security has rated this vulnerability as having a Moderate severity because successful exploitation requires user interaction to initiate a remote desktop session to an untrusted or compromised server, rather than targeting an exposed listening network service. While processing manipulated graphics display commands can lead to client-side memory corruption, the demonstrated impact is confined to terminating the client session via a crash. Server deployments of FreeRDP and sessions established solely with trusted remote hosts do not face exposure from arbitrary remote attackers.
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 | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | None |
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:H/I:N/A:N
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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