CVE-2026-75371 in SpaceDot
Summary
by MITRE • 08/24/2026
An integer handling flaw in the cobs_decode function of SpaceDot AcubeSAT OBC software commit eaf90ec allows physically-proximate attackers with UART access to cause a Denial of Service (DoS) via a crafted input.
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Analysis
by VulDB Data Team • 08/24/2026
The vulnerability identified in the SpaceDot AcubeSAT On-Board Computer software represents a critical security flaw within the Control and Orbital Subsystem, specifically located in the cobs_decode function associated with commit eaf90ec. This component is responsible for decoding packets using the COBS (Consistent Overhead Byte Stuffing) protocol, which is commonly employed in embedded systems to ensure data integrity during transmission over serial interfaces like UART. The core technical flaw stems from an integer handling error that occurs when processing malformed or crafted input sequences. In a properly implemented decoder, bounds checking and length validation are essential to prevent buffer overflows or logic errors. However, the specific implementation in this software fails to adequately validate the size of incoming data structures before performing arithmetic operations related to decoding offsets or array indexing. This lack of rigorous input sanitization allows an attacker who can inject specially crafted byte sequences into the UART interface to trigger undefined behavior within the application's memory space.
From a technical perspective, integer handling flaws often manifest as off-by-one errors, signedness issues, or overflow conditions that lead to out-of-bounds memory access. In this context, the cobs_decode function likely calculates buffer indices based on input data without verifying that these calculated values remain within the allocated heap or stack boundaries. When a physically proximate attacker with UART access provides an input designed to exploit this miscalculation, it can result in a crash of the decoding process or potentially corrupt adjacent memory structures. The immediate operational impact is a Denial of Service condition where the On-Board Computer may become unresponsive, freeze, or require a hard reset to recover. For satellite operations, such instability poses significant risks as it can interrupt telemetry downlinking, command execution, and attitude control functions, thereby compromising the mission's continuity and potentially leading to loss of vehicle control if recovery mechanisms are insufficient.
The attack vector requires physical proximity and direct access to the UART interface, which typically implies that an attacker must have gained unauthorized physical access to the satellite hardware or its ground station equipment during manufacturing, testing, or maintenance phases. This aligns with the ATT&CK framework technique T1059 Command and Scripting Interpreter if interpreted broadly as input manipulation leading to system compromise, but more accurately reflects initial access vectors associated with Physical Access (TA0043) and potentially Exploitation for Impact via Denial of Service. The vulnerability is categorized under CWE-120 Buffer Copy without Checking Size of Input or related integer overflow classifications such as CWE-190 Integer Overflow or Wraparound, depending on the exact nature of the arithmetic failure within the decoder logic. These standards highlight the fundamental principle that input data must never be trusted and must always be validated against expected constraints before processing.
Mitigation strategies for this vulnerability involve both immediate patching and long-term architectural improvements. The primary remediation is to apply a software update that corrects the cobs_decode function by implementing strict bounds checking on all buffer indices derived from decoded input data. Developers should ensure that any calculated offsets are validated against the maximum size of the destination buffer before memory access occurs. Additionally, incorporating fuzzing techniques during the development lifecycle can help identify similar integer handling flaws in other parts of the firmware. From a defense-in-depth perspective, restricting physical access to UART ports through hardware design changes or secure boot mechanisms is crucial. Furthermore, implementing watchdog timers and robust error recovery routines within the OBC software can mitigate the impact of such DoS events by automatically resetting affected subsystems without requiring manual intervention, thereby enhancing the overall resilience of the satellite's operational environment against both accidental faults and malicious exploitation attempts.