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).

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
FreeRDP FreeRDP unaffected
Version Status Constraints
0 affected < 3.29.0
3.29.0 unaffected —

No data.

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Project Subscriptions

Vendors Products
Freerdp Subscribe
Freerdp Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/FreeRDP/FreeRDP/commit/1cc783d4c78bd2f66d3a8582dfe70a663d141444 cve-icon
https://github.com/FreeRDP/FreeRDP/commit/5370fb26fbf034ecd11d3026b6ad639b5fff493f cve-icon
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pfxq-3qmw-8vjx cve-icon
https://www.vulncheck.com/advisories/freerdp-before-denial-of-service-via-serial-devicecontrol cve-icon
History

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: 2026-08-01T12:22:18.294Z

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

Link: CVE-2026-67303

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses