CVE-2025-61910: NASA ION-DTN DoS Vulnerability

CVE-2025-61910 Overview

CVE-2025-61910 is a Denial of Service (DoS) vulnerability in NASA's Interplanetary Overlay Network (ION), an implementation of Delay/Disruption Tolerant Networking (DTN). The vulnerability exists in ION-DTN version 4.1.3s and is triggered when processing a malformed BPv7 bundle with a crafted extension block. This flaw causes uncontrolled memory allocation, leading to receiver thread termination and service disruption.

Critical Impact

A remote attacker can send a specially crafted BPv7 bundle to crash the ION-DTN receiver thread, causing a complete Denial of Service for space communication network nodes.

Affected Products

• NASA ION-DTN version 4.1.3s
• BPv7 (Bundle Protocol version 7) implementations using ION-DTN
• Systems relying on Delay/Disruption Tolerant Networking infrastructure

Discovery Timeline

• 2025-10-07 - CVE-2025-61910 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-61910

Vulnerability Analysis

This vulnerability stems from improper handling of CBOR-encoded extension blocks within BPv7 bundles. When the ION-DTN receiver processes a malformed extension block, it encounters an integer type conversion issue that results in catastrophic memory allocation failure.

The vulnerable extension block begins with the byte sequence 0x85070201005bbb0e20b4ea001a000927c0.... The leading byte 0x85 indicates a CBOR array containing five elements. The first four elements are numeric values (0x07, 0x02, 0x01, 0x00), but the fifth element is a byte string of length 27. When this byte string is processed instead of an expected numeric value, the parser derives an extremely large block length value.

The vulnerability is classified under CWE-789 (Memory Allocation with Excessive Size Value), indicating that the application fails to properly validate size parameters before memory allocation operations.

Root Cause

The root cause lies in the bei.c file at line 764, where an unsigned integer blockLength is converted to a 32-bit signed integer blkSize. This unsigned-to-signed conversion causes blkSize to hold the negative value of -369092043. When this value is subsequently passed to MTAKE(blkSize), it undergoes implicit conversion to a 64-bit unsigned value, resulting in an astronomically large memory allocation request that the system cannot fulfill.

The fundamental issue is the lack of bounds checking before the type conversion and the absence of validation to ensure the block length falls within reasonable limits for memory allocation.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can remotely send a specially crafted BPv7 bundle containing the malicious extension block to any ION-DTN node. Upon receipt, the vulnerable parsing code will attempt to allocate an impossibly large memory region, causing the receiver thread to crash.

The malformed extension block exploits the CBOR parsing logic by substituting an expected numeric field with a carefully constructed byte string. This causes the parser to misinterpret the data and derive an invalid block length value.

For detailed technical analysis of the vulnerable code path, refer to the GitHub source code reference and the GitHub Security Advisory.

Detection Methods for CVE-2025-61910

Indicators of Compromise

• Unexpected termination of ION-DTN receiver threads without clear cause
• Memory allocation failure logs in ION-DTN service logs
• Inbound BPv7 bundles containing extension blocks with CBOR byte strings in unexpected positions
• System resource exhaustion alerts related to memory allocation attempts

Detection Strategies

• Monitor ION-DTN service logs for memory allocation errors or thread termination events
• Implement network traffic analysis to detect malformed BPv7 bundles with anomalous extension block structures
• Deploy intrusion detection rules to identify bundles containing the signature byte pattern 0x85070201005b in extension blocks
• Configure alerting for ION-DTN process crashes or restarts

Monitoring Recommendations

• Establish baseline metrics for ION-DTN receiver thread health and memory usage patterns
• Implement real-time monitoring of BPv7 bundle processing success and failure rates
• Configure automated alerts for any ION-DTN service interruptions or unexpected restarts
• Review incoming network traffic for CBOR-encoded payloads with excessive length indicators

How to Mitigate CVE-2025-61910

Immediate Actions Required

• Evaluate the criticality of ION-DTN deployments and consider temporarily isolating vulnerable nodes from untrusted network segments
• Implement network-level filtering to block malformed BPv7 bundles where possible
• Monitor ION-DTN service health closely for signs of exploitation attempts
• Review the GitHub Security Advisory for the latest mitigation guidance

Patch Information

As of the publication date, no patched versions of BPv7 within ION-DTN are available. Organizations should monitor the official NASA JPL ION-DTN repository for security updates and apply patches immediately upon release. The vulnerability affects version 4.1.3s and potentially other versions using the same extension block parsing logic.

Workarounds

• Restrict network access to ION-DTN nodes to trusted sources only using firewall rules or network segmentation
• Implement application-level input validation to reject BPv7 bundles with suspicious extension block structures before they reach the vulnerable parsing code
• Consider deploying a proxy or gateway that validates bundle integrity before forwarding to ION-DTN nodes
• If operationally feasible, disable processing of extension blocks until a patch is available

# Example: Network isolation configuration for ION-DTN nodes
# Restrict incoming DTN traffic to known, trusted peer addresses
iptables -A INPUT -p udp --dport 4556 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p udp --dport 4556 -j DROP