CVE-2026-63117
Description
A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol. An authenticated Remote Desktop Protocol (RDP) client can trigger a denial of service by sending a specially crafted DVI ADPCM frame. By advertising specific nBlockAlign and nChannels values, a division-by-zero error occurs in the rdpsnd_server_select_format function. This vulnerability leads to the termination of the server-side rdpsnd channel process, causing a denial of service.
Statement
A divide-by-zero flaw was found in FreeRDP's rdpsnd audio channel server implementation. An authenticated remote RDP client can send malformed DVI ADPCM audio parameters (nBlockAlign=8, nChannels=2) during format selection in rdpsnd_server_select_format. This triggers an unhandled SIGFPE signal when calculating audio frames, crashing the server-side rdpsnd process and resulting in a denial of service for remote desktop audio capabilities.
Mitigation
To mitigate this issue, administrators can disable audio redirection on the FreeRDP server configuration if remote audio support is not strictly required.
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 | Low | N/A | Low |
| User Interaction | None | 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:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
A Divide by Zero results in a crash.
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