FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in channels/serial/client/serial_main.c. When serial device redirection is enabled and a server-controlled IRP_MJ_DEVICE_CONTROL request specifies an unsupported IOCTL with a non-zero OutputBufferLength, CommDeviceIoControl() can fail with BytesReturned = 0, causing the mismatch to trigger the assertion and abort the client process (denial of service).
Advisories

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Fixes

Solution

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Workaround

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History

Fri, 07 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 03 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sat, 01 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
Description FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in channels/serial/client/serial_main.c. When serial device redirection is enabled and a server-controlled IRP_MJ_DEVICE_CONTROL request specifies an unsupported IOCTL with a non-zero OutputBufferLength, CommDeviceIoControl() can fail with BytesReturned = 0, causing the mismatch to trigger the assertion and abort the client process (denial of service).
Title FreeRDP before 3.29.0 Denial of Service via serial DeviceControl
First Time appeared Freerdp
Freerdp freerdp
Weaknesses CWE-617
CPEs cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*
Vendors & Products Freerdp
Freerdp freerdp
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-03T19:45:09.671Z

Reserved: 2026-07-29T13:04:41.947Z

Link: CVE-2026-67303

cve-icon Vulnrichment

Updated: 2026-08-03T19:44:33.608Z

cve-icon NVD

Status : Received

Published: 2026-08-01T13:16:59.833

Modified: 2026-08-03T20:17:26.603

Link: CVE-2026-67303

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-01T12:22:18Z

Links: CVE-2026-67303 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-02T03:00:13Z

Weaknesses