CVE-2026-41144: F´ (F Prime) Framework RCE Vulnerability

CVE-2026-41144 Overview

A critical integer overflow vulnerability exists in NASA's F´ (F Prime) framework, a software platform designed for spaceflight and embedded software applications. Prior to version 4.2.0, the framework contains a bounds check vulnerability where U32 addition wraps around on overflow, allowing attackers to bypass file offset validation. Combined with missing path sanitization in Svc/FileUplink/File.cpp, this enables arbitrary file write at any offset, ultimately leading to remote code execution on embedded targets.

Critical Impact

Attackers can achieve arbitrary file write and remote code execution on embedded spaceflight systems by exploiting integer overflow in bounds checking and lack of path sanitization.

Affected Products

• F´ (F Prime) Framework versions prior to 4.2.0
• NASA F Prime embedded software deployments
• Spaceflight and embedded applications built on vulnerable F Prime versions

Discovery Timeline

• April 22, 2026 - CVE CVE-2026-41144 published to NVD
• April 22, 2026 - Last updated in NVD database

Technical Details for CVE-2026-41144

Vulnerability Analysis

The vulnerability resides in the bounds checking logic within the F´ framework's file upload handling. The check byteOffset + dataSize > fileSize uses U32 (unsigned 32-bit integer) addition, which wraps around to zero when the sum exceeds the maximum U32 value of 0xFFFFFFFF. An attacker can craft a malicious DataPacket with specifically chosen values (such as byteOffset=0xFFFFFF9C and dataSize=100) that overflow to 0, completely bypassing the bounds validation.

What makes this vulnerability particularly dangerous is that it is a pure logic bug—memory safety tools like AddressSanitizer (ASAN) cannot detect it because all memory accesses remain within valid buffers. The corruption occurs at the file I/O level, not in memory operations.

Root Cause

The root cause is CWE-190 (Integer Overflow or Wraparound). The bounds check uses unsigned 32-bit arithmetic without overflow protection. When byteOffset and dataSize values are chosen such that their sum exceeds 0xFFFFFFFF, the result wraps around, defeating the protective check. Additionally, the file path handling in Svc/FileUplink/File.cpp (lines 20-31) performs no sanitization on the destination file path, enabling path traversal attacks.

Attack Vector

The attack is network-accessible and requires no authentication or user interaction. An attacker sends a crafted DataPacket through the network interface with:

1. A byteOffset value near the U32 maximum (e.g., 0xFFFFFF9C)
2. A dataSize value that causes integer overflow when added (e.g., 100)
3. The overflow results in the bounds check evaluating to 0, which passes validation
4. The file write proceeds at the original ~4GB offset using the unsanitized file path
5. Combined with path traversal, arbitrary data can be written to any file at any offset

This can overwrite critical system files, configuration data, or inject malicious code into executable regions, leading to remote code execution. The attack requires no authentication and can be executed over the network.

Detection Methods for CVE-2026-41144

Indicators of Compromise

• Unexpected file modifications at large offsets (near 4GB boundaries)
• Anomalous DataPacket requests with unusually large byteOffset values approaching 0xFFFFFFFF
• File upload operations targeting paths outside expected directories
• Suspicious file writes to system-critical locations or executables

Detection Strategies

• Monitor file upload operations for byteOffset values greater than 0xFFFFFFF0 combined with non-zero dataSize
• Implement integrity monitoring on critical system files and executables
• Deploy network monitoring to detect malformed DataPacket messages with suspicious parameter combinations
• Use application-level logging to track all file I/O operations with offset values

Monitoring Recommendations

• Enable verbose logging for the FileUplink component in F´ deployments
• Implement file integrity monitoring (FIM) on embedded targets for critical system directories
• Configure network intrusion detection rules to flag packets with U32 overflow patterns
• Establish baseline behavior for file upload operations and alert on deviations

How to Mitigate CVE-2026-41144

Immediate Actions Required

• Upgrade F´ (F Prime) framework to version 4.2.0 or later immediately
• Audit all embedded deployments for vulnerable F Prime versions
• Review file upload logs for any evidence of exploitation attempts
• Implement network segmentation to restrict access to embedded targets running vulnerable versions

Patch Information

NASA has released version 4.2.0 of the F´ framework which addresses this vulnerability. The fix is available in commit cacdd555456bd83ab395b521d56c0330470ea798. Organizations should upgrade to the patched version as the primary mitigation. Full details are available in the GitHub Security Advisory GHSA-qmvv-rxh4-ccqh.

Workarounds

• No known workarounds are available according to the security advisory
• Network isolation of affected systems is strongly recommended as a temporary measure
• Restrict network access to file upload interfaces on embedded targets
• Monitor all file operations closely until patching is completed