FreeRDP before 3.29.0 contains a reachable assertion (WINPRASSERT(OutputBufferLength == BytesReturned)) in serialprocessirpdevicecontrol() in channels/serial/client/serialmain.c. When serial device redirection is enabled and a server-controlled IRPMJDEVICE_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).
{
"cwe_ids": [
"CWE-617"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67303.json",
"cna_assigner": "VulnCheck"
}