CVE-2026-67304
Description
A null pointer dereference flaw in FreeRDP allows a remote attacker to cause a denial of service (DoS) via specially crafted smartcard requests. If reader-state decoding fails, the system attempts to free uninitialized states during cleanup, resulting in a process crash.
Statement
This Moderate-impact vulnerability causes a denial of service (DoS) in FreeRDP clients and proxies. If smartcard redirection is enabled, an attacker (via a malicious server or proxy client) can send specially crafted smartcard IRP requests to trigger a null pointer dereference during cleanup.
Note: FreeRDP packages shipped in Red Hat Enterprise Linux (RHEL) 9 and older are not affected.
Mitigation
To mitigate this issue, disable smartcard redirection in FreeRDP client configurations if smartcard functionality is not required. This can typically be achieved by launching the `xfreerdp` client without the `/smartcard` option, or by explicitly setting `/smartcard:no` if a configuration file is used. Disabling smartcard redirection will prevent the use of smartcard devices with FreeRDP 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 | 6.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | 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:R/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
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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