CVE-2026-92151 in F Prime
Summary
by MITRE • 10/14/2026
F´ (F Prime) is a framework that enables development and deployment of spaceflight and other embedded software applications. Prior to 4.2.0, Svc::Ccsds::SpacePacketDeframer dataIn_handler is vulnerable because the handler treats the minimum packet-length condition as FW_ASSERT rather than rejecting and returning the buffer. When a CCSDS telecommand frame leaves a payload of six bytes or fewer after TcDeframer removes its header and trailer, the assertion aborts or resets the flight-software process, causing denial of service. This issue is fixed in version 4.2.0.
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Analysis
by VulDB Data Team • 10/14/2026
The F Prime framework serves as a critical infrastructure for developing and deploying embedded software applications within spaceflight systems and other high-reliability environments. In versions prior to 4.2.0, the Svc::Ccsds module contains a significant logic error in its SpacePacketDeframer component that compromises system stability when processing malformed or truncated CCSDS telecommand frames. The vulnerability stems from an improper handling of boundary conditions during packet parsing, specifically regarding minimum payload length validation. Instead of implementing robust input validation to reject invalid data structures gracefully, the software relies on a fatal assertion mechanism to handle these edge cases. This design choice fundamentally violates secure coding principles for embedded systems where graceful degradation is preferred over catastrophic failure.
The technical flaw occurs within the dataIn_handler function responsible for processing incoming CCSDS packets. When a telecommand frame arrives with insufficient payload size, specifically six bytes or fewer after the header and trailer have been removed by the TcDeframer logic, the system triggers an FW_ASSERT condition rather than returning an error code to discard the buffer. In embedded environments such as spacecraft flight software, assertions are typically configured to halt execution or reset the process upon failure. Consequently, this improper handling leads directly to a denial of service scenario where the affected flight-software process aborts or resets unexpectedly. This behavior disrupts continuous operations and can lead to loss of control over critical subsystems if not properly mitigated by higher-level watchdog mechanisms.
From a security taxonomy perspective, this vulnerability aligns with CWE-617, which describes Reachable Assertion issues where the assertion is triggered under normal operational conditions involving malformed input rather than only during programming errors or internal logic failures. Furthermore, in the context of adversarial tactics, this flaw relates to ATT&CK technique T1499, Endpoint Denial of Service, as an attacker could potentially exploit this condition by transmitting specially crafted CCSDS frames designed to trigger the assertion repeatedly, thereby causing persistent service disruption. The lack of proper input validation and error handling represents a classic instance of insufficient defensive coding practices in safety-critical software.
The operational impact of this vulnerability is severe due to the nature of spaceflight applications where continuous availability is paramount. A reset or abort of the flight-software process can result in temporary loss of telemetry, command execution delays, or complete mission interruption depending on the redundancy architecture and recovery protocols implemented at the system level. While some systems may have watchdog timers that automatically restart crashed processes, frequent resets can degrade performance, increase latency, and potentially lead to data corruption if state is not properly preserved across reboots. For missions with limited ground contact windows, such disruptions could result in missed opportunities for critical command uploads or science data downlinks.
This issue was addressed in version 4.2.0 of the F Prime framework by modifying the Svc::Ccsds::SpacePacketDeframer to properly validate packet lengths and reject buffers that do not meet minimum size requirements without triggering fatal assertions. The fix ensures that invalid packets are discarded gracefully, allowing the system to maintain operational continuity even when receiving malformed data from potentially compromised or malfunctioning sources. Organizations utilizing F Prime for embedded software development should prioritize upgrading to version 4.2.0 or later to mitigate this risk. Additionally, implementing defense-in-depth strategies such as network-level filtering of CCSDS traffic and rigorous testing with fuzzed inputs can further reduce the attack surface associated with packet parsing vulnerabilities in spaceflight systems.