CVE-2026-114042 in FreeRDP
Summary
by MITRE • 10/22/2026
FreeRDP 3.32.0 contains a use-after-free vulnerability in the drdynvc channel that frees a pool-owned stream with the owned-stream deallocator when totalLength is smaller than the chunk size. A malicious RDP server can send a single well-formed Virtual Channel PDU to trigger the free and crash the client during teardown.
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Analysis
by VulDB Data Team • 10/22/2026
The vulnerability identified in FreeRDP version 3.32.0 represents a critical memory safety flaw within the dynamic virtual channel implementation, specifically classified under Common Weakness Enumeration CWE-416 as Use After Free. This defect occurs during the processing of Virtual Channel Protocol Data Units where the application fails to adequately validate buffer boundaries before performing deallocation operations. The core technical issue arises when the total length specified in a received packet is smaller than the expected chunk size for data extraction. In such scenarios, the internal logic incorrectly proceeds to invoke the owned-stream deallocator on a memory pool that has already been freed or is otherwise invalid due to the mismatched length parameters. This logical error leads directly to a use-after-free condition where the application attempts to access or manipulate memory that it no longer owns, resulting in undefined behavior and typically causing an immediate crash of the client process during teardown phases.
From an operational perspective, this vulnerability allows for remote code execution potential if exploited with additional techniques such as heap spraying, although the primary observable impact is a denial of service through application termination. A malicious RDP server can exploit this flaw by crafting a single, well-formed Virtual Channel PDU that triggers the erroneous deallocation path. The attacker does not need to send multiple packets or maintain an ongoing session; a single crafted packet sent during specific phases of channel initialization or teardown is sufficient to trigger the crash. This significantly lowers the barrier for exploitation compared to vulnerabilities requiring complex multi-stage payloads, making it particularly dangerous in environments where users connect to untrusted or compromised remote desktop servers. The impact extends beyond simple availability loss, as memory corruption issues like use-after-free can potentially be leveraged to execute arbitrary code by controlling heap layout and overwriting function pointers within the freed memory region.
This vulnerability aligns with MITRE ATT&CK technique T1203, which covers Exploitation for Client Execution, specifically in contexts where a client application is tricked into processing malicious input from a server-side actor. The lack of strict validation on packet length fields relative to chunk sizes indicates a failure in implementing robust input sanitization and boundary checks, which are fundamental requirements for secure network protocol implementations. To mitigate this risk, users must immediately update FreeRDP to the latest patched version where developers have implemented stricter length validations before invoking stream deallocation routines. Additionally, organizations should enforce strict policies regarding connections to untrusted RDP servers and consider deploying application whitelisting or sandboxing solutions to limit the impact of potential client-side crashes. Network segmentation can also help isolate critical workstations from potentially hostile remote desktop environments, reducing the attack surface for such protocol-level exploits until patches are fully deployed across all endpoints.