CVE-2026-121387
Description
A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can cause a Denial of Service (DoS) by sending truncated audio packets to a connecting client. Because the audio decoder fails to verify buffer boundaries before processing incoming frames, it attempts to read memory beyond the allocated buffer, causing the client application to crash.
Statement
This vulnerability is rated as Moderate severity because exploitation requires an active connection to an untrusted or compromised RDP server, limiting the blast radius to client-side denial of service rather than code execution or host takeover. FreeRDP is primarily utilized within Red Hat environments as a client application to access known enterprise systems. Exposure is constrained to scenarios where an end user connects to a hostile endpoint that attempts to negotiate the vulnerable GSM610 audio channel. Environments that restrict outbound remote desktop traffic to verified internal servers are not at risk.
Mitigation
Avoid establishing remote desktop sessions to untrusted or unverified RDP servers. If connections to external or untrusted endpoints are necessary, disable audio redirection to prevent the client from negotiating the rdpsnd audio channel. When launching the FreeRDP command-line client, ensure sound redirection options such as `/sound` are omitted. In graphical remote desktop clients (such as Remmina), disable audio output redirection within the connection profile settings.
Caveats: Disabling audio redirection prevents audio output generated on the remote host from being played back on the local workstation.
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)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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