CVE-2026-67973 in cFS
Summary
by MITRE • 08/04/2026
An issue in the CFDP receive path of NASA cFS v7.0.1 allows attackers to cause a Denial of Service (DoS) via replaying final CFDP PDUs.
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Analysis
by VulDB Data Team • 08/04/2026
The vulnerability resides within the Communication Framework for Space Systems (cFS) version 7.0.1, specifically in the Consultative Committee for Space Data Systems (CCSDS) File Delivery Protocol (CFDP) receive implementation. This flaw represents a critical denial of service condition that can be exploited through strategic replay attacks against final CFDP protocol data units. The cFS is a widely deployed software framework for space applications that provides standardized communication protocols and services for spacecraft operations, making this vulnerability particularly concerning in mission-critical environments where system reliability is paramount.
The technical root cause involves improper state handling within the CFDP receive path logic that fails to properly validate or reject replayed final PDUs. When an attacker successfully replays these final protocol units, the receiving cFS component enters an inconsistent operational state where it cannot properly process subsequent legitimate data transfers. This occurs because the system's internal state machine does not adequately distinguish between legitimate and malicious replay attempts, leading to a cascade of errors that ultimately results in service disruption. The vulnerability is classified under CWE-457 as use of uninitialized variable, though more specifically manifests as improper state management within protocol handling mechanisms. This flaw aligns with ATT&CK technique T1499.002 which describes endpoint denial of service via resource consumption or system instability.
The operational impact extends beyond simple service interruption to potentially compromise the entire spacecraft communication infrastructure. In space applications, where bandwidth and processing resources are severely constrained, a DoS condition can prevent critical mission data from being received or processed, leading to potential mission failure. The vulnerability is particularly dangerous because it requires minimal resources to exploit - an attacker need only replay previously transmitted final PDUs to trigger the condition. This makes it difficult to detect and mitigate in real-time operations where network monitoring may be limited. The affected cFS implementation impacts various space missions that rely on reliable file transfer protocols for command and telemetry data, particularly those using the CCSDS standard for inter-spacecraft communication.
Mitigation strategies should focus on implementing proper replay detection mechanisms within the CFDP receive path, including timestamp validation and sequence number tracking to prevent duplicate processing. System administrators should consider deploying network segmentation to limit potential attack vectors and implement rate limiting to reduce the effectiveness of replay attacks. Additionally, regular firmware updates to patched versions of cFS should be prioritized, as this vulnerability represents a known issue that has been addressed in subsequent releases. The implementation of intrusion detection systems specifically designed for space protocols can help identify anomalous replay patterns before they cause system instability. Organizations should also conduct thorough security assessments of their space communication systems to identify similar state management vulnerabilities across other protocol implementations within their cFS deployments, as the underlying architectural flaw may exist in related components.