CVE-2026-5475 Overview
A memory corruption vulnerability has been identified in NASA core Flight System (cFS) affecting versions up to 7.0.0. This vulnerability impacts the CFE_SB_TransmitMsg function within the cfe_sb_priv.c file, specifically in the CCSDS Header Size Handler component. An attacker capable of manipulating data through this component can trigger memory corruption conditions.
Critical Impact
Memory corruption in flight software systems can lead to unpredictable behavior, potential denial of service, or compromise of spacecraft command and telemetry systems.
Affected Products
- NASA cFS (core Flight System) versions up to 7.0.0
- cfe_sb_priv.c component - CCSDS Header Size Handler
- Systems implementing CFE_SB_TransmitMsg function
Discovery Timeline
- 2026-04-03 - CVE-2026-5475 published to NVD
- 2026-04-07 - Last updated in NVD database
Technical Details for CVE-2026-5475
Vulnerability Analysis
This vulnerability falls under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the Software Bus (SB) message transmission functionality of NASA's core Flight System, a reusable software framework designed for spacecraft flight software applications.
The affected function CFE_SB_TransmitMsg handles CCSDS (Consultative Committee for Space Data Systems) packet headers, which are standard protocols used in space communications. When processing malformed or specially crafted CCSDS header size values, the function fails to properly validate memory boundaries, potentially leading to out-of-bounds memory operations.
The vulnerability requires adjacent network access and low-privilege authentication, limiting the attack surface to threat actors with local network presence within the spacecraft's software environment or ground control systems with direct communication capabilities.
Root Cause
The root cause stems from improper bounds checking in the CCSDS Header Size Handler when processing message transmissions through the Software Bus. The CFE_SB_TransmitMsg function does not adequately validate header size parameters before performing memory operations, creating conditions where memory corruption can occur through crafted input manipulation.
Attack Vector
The attack requires adjacent network access (AV:A), meaning the attacker must have access to the local network segment where the cFS instance operates. This could include:
- Ground control station networks with direct communication links
- Development or testing environments running cFS instances
- Networked simulation environments
Exploitation involves crafting malicious CCSDS packets with manipulated header size values that, when processed by the vulnerable CFE_SB_TransmitMsg function, cause the system to perform memory operations outside intended buffer boundaries. The low attack complexity and no user interaction requirement indicate that once network adjacency is achieved, exploitation is straightforward.
The vulnerability mechanism involves improper handling of CCSDS header size values in the message transmission path. When the CFE_SB_TransmitMsg function processes messages with unexpected header dimensions, memory corruption can occur due to insufficient boundary validation. Technical details and the original issue report are available via GitHub cFS Issue #953.
Detection Methods for CVE-2026-5475
Indicators of Compromise
- Unexpected crashes or restarts of cFS application processes
- Abnormal memory allocation patterns in Software Bus components
- CCSDS packets with malformed or unusual header size values in telemetry logs
- Memory access violations or segmentation faults in cfe_sb_priv.c related functions
Detection Strategies
- Implement memory integrity monitoring for cFS processes to detect corruption events
- Deploy network traffic analysis to identify malformed CCSDS packets with anomalous header sizes
- Enable verbose logging for Software Bus message transmission operations
- Utilize static code analysis tools to identify similar boundary condition issues in custom cFS modules
Monitoring Recommendations
- Monitor system logs for memory-related errors in the CFE_SB subsystem
- Implement runtime memory protection mechanisms where supported by the target platform
- Establish baseline metrics for normal Software Bus message patterns to detect anomalies
- Review ground system network traffic for unexpected CCSDS packet structures
How to Mitigate CVE-2026-5475
Immediate Actions Required
- Audit all cFS deployments to identify instances running affected versions up to 7.0.0
- Restrict network access to cFS instances to authorized systems only
- Implement additional input validation for CCSDS header processing where possible
- Review and enhance network segmentation between ground systems and flight software environments
Patch Information
At the time of publication, the NASA cFS project had been informed of this vulnerability through GitHub Issue #953 but has not yet released an official patch or response. Organizations should monitor the NASA cFS GitHub repository for security updates and patch releases.
Additional vulnerability details are available through VulDB Entry #355079.
Workarounds
- Implement network-level filtering to block malformed CCSDS packets before they reach cFS instances
- Add custom input validation wrappers around CFE_SB_TransmitMsg function calls to validate header sizes
- Deploy the cFS in isolated network segments with strict access controls
- Consider implementing application-level sandboxing or memory protection mechanisms where platform capabilities allow
# Network isolation configuration example for cFS environments
# Restrict Software Bus communication to authorized endpoints only
iptables -A INPUT -p udp --dport 1234 -s trusted_ground_station_ip -j ACCEPT
iptables -A INPUT -p udp --dport 1234 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
