CVE-2026-121403
Description
A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can trigger a Denial of Service (DoS) by sending a malformed drive redirection request with truncated data to a connected client. This request causes the client's drive background worker to exit unexpectedly while leaving the communication channel active. Consequently, subsequent incoming requests accumulate unbounded in memory, exhausting system resources and disrupting the active remote desktop session.
Statement
This vulnerability is rated as having a Moderate impact because it exclusively leads to client-side denial of service without permitting arbitrary code execution or privilege escalation. Exploitation requires a user to connect an affected client session to a malicious or compromised RDP server with drive redirection features actively utilized. Typical usage against trusted internal infrastructure remains unaffected by this flaw.
Mitigation
Do not enable local drive redirection when initiating client connections (avoid using the `/drive` command-line option), and connect exclusively to trusted RDP hosts.
Caveats:
Disabling drive redirection prevents sharing local storage devices or directories with the remote desktop environment. No system reload or service restart is required as this issue only affects client-side interactive sessions.
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 | 4.3 | N/A | 4.3 |
| 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 | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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