FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in… (CVE-2026-67303)
FreeRDP versions before 3.29.0 contain a reachable assertion failure in the serial device redirection component. This occurs when a server-controlled device control request specifies an unsupported IOCTL with a non-zero output buffer length, causing a mismatch that triggers an assertion and aborts the client process. The issue results in a denial of service but does not impact confidentiality or integrity.
AI Analysis
Technical Summary
The vulnerability in FreeRDP prior to version 3.29.0 involves an assertion failure (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in the function serial_process_irp_device_control() within the serial device redirection channel. When serial device redirection is enabled, and the server sends an IRP_MJ_DEVICE_CONTROL request with an unsupported IOCTL and a non-zero OutputBufferLength, the CommDeviceIoControl() call can fail with BytesReturned set to zero. This discrepancy causes the assertion to fail, leading to the client process aborting and resulting in a denial of service condition.
Potential Impact
An attacker controlling the server side of a FreeRDP session can cause the client process to abort by sending a specially crafted device control request. This leads to a denial of service on the client side. There is no impact on confidentiality or integrity according to the CVSS vector and description.
Mitigation Recommendations
A fix is available in FreeRDP version 3.29.0. Users should upgrade to version 3.29.0 or later to remediate this vulnerability. No vendor advisory was provided to indicate alternative mitigations or temporary fixes.
FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in… (CVE-2026-67303)
Description
FreeRDP versions before 3.29.0 contain a reachable assertion failure in the serial device redirection component. This occurs when a server-controlled device control request specifies an unsupported IOCTL with a non-zero output buffer length, causing a mismatch that triggers an assertion and aborts the client process. The issue results in a denial of service but does not impact confidentiality or integrity.
CVSS v3.1
Score 4.3medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in FreeRDP prior to version 3.29.0 involves an assertion failure (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in the function serial_process_irp_device_control() within the serial device redirection channel. When serial device redirection is enabled, and the server sends an IRP_MJ_DEVICE_CONTROL request with an unsupported IOCTL and a non-zero OutputBufferLength, the CommDeviceIoControl() call can fail with BytesReturned set to zero. This discrepancy causes the assertion to fail, leading to the client process aborting and resulting in a denial of service condition.
Potential Impact
An attacker controlling the server side of a FreeRDP session can cause the client process to abort by sending a specially crafted device control request. This leads to a denial of service on the client side. There is no impact on confidentiality or integrity according to the CVSS vector and description.
Mitigation Recommendations
A fix is available in FreeRDP version 3.29.0. Users should upgrade to version 3.29.0 or later to remediate this vulnerability. No vendor advisory was provided to indicate alternative mitigations or temporary fixes.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-4wq4-c34j-gg99
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-67303"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a6e6296bf32cb7a344f6a1c
Added to database: 08/01/2026, 21:18:14 UTC
Last enriched: 08/01/2026, 21:23:45 UTC
Last updated: 08/02/2026, 03:01:21 UTC
Views: 3
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