CVE-2026-67978 Overview
CVE-2026-67978 is a denial of service vulnerability in the Software Bus Network (SBN) UDP interface of NASA core Flight System (cFS) version 7.0.1. An unauthenticated remote attacker can transmit a crafted SBN frame to the affected interface and cause the target process to become unresponsive. The flaw is classified under [CWE-20: Improper Input Validation] and requires no authentication or user interaction, since the SBN interface listens on the network.
NASA cFS is an open-source framework used in flight software for spacecraft and embedded aerospace systems. The SBN component enables message passing between cFS instances across nodes, which makes availability of the interface central to inter-node communication.
Critical Impact
A single crafted UDP frame can disrupt inter-node messaging in cFS deployments, breaking availability of the affected flight software bus.
Affected Products
- NASA core Flight System (cFS) version 7.0.1
- SBN (Software Bus Network) UDP interface module
- Downstream projects and mission software bundling cFS v7.0.1
Discovery Timeline
- 2026-08-03 - CVE-2026-67978 published to the National Vulnerability Database
- 2026-08-04 - Last updated in NVD database
Technical Details for CVE-2026-67978
Vulnerability Analysis
The vulnerability resides in the SBN UDP interface, which accepts network frames intended for the cFS Software Bus Network. When the interface receives a malformed frame, insufficient validation of the frame contents leads to a condition that halts normal processing. The result is a denial of service against the SBN interface and, by extension, message-passing between cFS nodes.
Because SBN is used for inter-application and inter-node communication in cFS deployments, disruption of the interface can propagate to any subsystem that depends on cross-node messaging. In embedded aerospace or research environments, loss of the bus can prevent command and telemetry flow between components.
Root Cause
The root cause is improper input validation [CWE-20] on inbound SBN frames received by the UDP interface. The interface does not sufficiently verify frame structure or field values before acting on the data, allowing crafted input to place the interface into an unrecoverable state.
Attack Vector
The attack vector is network-based. An attacker with reachability to the SBN UDP port on a cFS v7.0.1 host transmits a crafted SBN frame. No credentials or user interaction are required. Refer to the GitHub Issue Report for technical context published by the maintainers.
No verified public proof-of-concept code is available. The vulnerability mechanism should be understood from the referenced upstream issue rather than reconstructed from synthetic examples.
Detection Methods for CVE-2026-67978
Indicators of Compromise
- Unexpected termination or unresponsive state of the SBN UDP interface process on cFS nodes running version 7.0.1
- Sudden loss of inter-node cFS message traffic without a corresponding operator action or scheduled maintenance
- Inbound UDP traffic to SBN ports from sources outside the expected cFS peer set
Detection Strategies
- Monitor host and application logs for SBN interface restarts, crashes, or halted message processing on cFS v7.0.1 instances
- Deploy network-based inspection to identify malformed SBN frames or SBN traffic originating from non-peer addresses
- Correlate loss of SBN heartbeat or peer-status messages with recent inbound UDP activity on the SBN listener port
Monitoring Recommendations
- Establish a baseline of expected SBN peers, source addresses, and frame rates, and alert on deviations
- Capture packet metadata for SBN UDP ports so post-incident analysis can identify crafted frames
- Track process health of cFS applications hosting the SBN UDP interface with automated availability checks
How to Mitigate CVE-2026-67978
Immediate Actions Required
- Restrict network reachability of SBN UDP ports to known cFS peer nodes using host firewalls or network ACLs
- Isolate cFS v7.0.1 systems on dedicated management or mission network segments away from general-purpose networks
- Monitor the upstream NASA cFS GitHub repository for a fixed release and apply it once available
Patch Information
At the time of publication, no vendor patch is referenced in the NVD entry for CVE-2026-67978. The upstream issue is tracked at the GitHub Issue Report. Operators should subscribe to the issue and to NASA cFS release notifications to obtain the fixed version when published.
Workarounds
- Enforce strict allow-lists on the SBN UDP listener so only trusted peer addresses can send frames
- Place cFS nodes behind a network segmentation boundary that blocks arbitrary external UDP traffic
- Where feasible, disable or replace the UDP SBN interface with an alternative transport limited to trusted links
# Configuration example: restrict SBN UDP traffic to known peers using iptables
# Replace <SBN_PORT> with the configured SBN UDP port and <PEER_IP> with each trusted cFS peer
iptables -A INPUT -p udp --dport <SBN_PORT> -s <PEER_IP_1> -j ACCEPT
iptables -A INPUT -p udp --dport <SBN_PORT> -s <PEER_IP_2> -j ACCEPT
iptables -A INPUT -p udp --dport <SBN_PORT> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
