CVE-2026-92155 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, Fw::FilePacket deserialization used by Svc::FileUplink is vulnerable because Header deserialization casts the byte to the Type enum without validating its range and FilePacket::fromSerialBuffer reaches a default FW_ASSERT. When a network file packet contains an unknown file-packet type byte, the assertion aborts or resets the default Ref application 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 resource-constrained environments. A significant security flaw was identified in the deserialization logic associated with the Svc::FileUplink component, specifically affecting versions prior to 4.2.0. This vulnerability centers on the handling of file packet headers during network transmission, where the system fails to adequately validate input data before processing it as a specific enumeration type. The core technical flaw lies in how the Fw::FilePacket class processes incoming byte streams. When deserializing a header from a serial buffer, the implementation directly casts an arbitrary byte value into a Type enum without performing any range validation or bounds checking. This lack of input sanitization means that if a network file packet contains a type identifier byte that does not correspond to one of the defined valid types in the enumeration, the resulting cast produces an invalid state within the application logic.
This improper handling leads directly to a denial of service condition through assertion failure. In embedded systems like those built on F Prime, assertions are often configured to trigger hardware resets or aborts when unexpected conditions occur, serving as a safeguard against undefined behavior in low-level code. Consequently, when an attacker or a malfunctioning system sends a file packet with an unrecognized type byte, the FilePacket::fromSerialBuffer method encounters this invalid enum value and triggers a FW_ASSERT macro. This assertion failure causes the default Ref application process to abort or reset entirely. For spaceflight applications where continuous operation is paramount, such unexpected resets can lead to mission-critical downtime, loss of telemetry data, or complete system unavailability until manual intervention occurs. The vulnerability effectively allows any entity capable of injecting network packets into the uplink channel to disrupt service stability by simply sending a packet with an invalid type identifier.
From a classification perspective, this vulnerability aligns closely with CWE-20 Improper Input Validation and CWE-754: Improper Check for Unusual or Exceptional Conditions. The failure to validate that the input byte falls within the expected range of valid enum values represents a classic case of insufficient validation before processing. Furthermore, in the context of the MITRE ATT&CK framework, this flaw can be leveraged as part of an Impact tactic, specifically under techniques related to Service Stop or Resource Hijacking, where availability is compromised through system crashes rather than data exfiltration or modification. The attack vector typically involves network access, making it a remote vulnerability if the uplink interface is exposed to untrusted networks, although in many embedded contexts, physical or local network access may be required depending on deployment architecture.
Mitigation strategies primarily involve upgrading to version 4.2.0 of the F Prime framework, where this deserialization logic has been corrected to include proper range validation before casting bytes to enum types. For systems that cannot immediately upgrade, developers should implement defensive coding practices by adding explicit bounds checking for any byte values intended to map to enumerated types in custom serialization modules. Additionally, securing the network interfaces used for file uplinks through strict access control lists and encryption can reduce the risk of exploitation by unauthorized actors. Regular security audits of embedded communication protocols are recommended to ensure that all deserialization routines adhere to secure coding standards that prevent type confusion and assertion-based denial of service attacks.