CVE-2025-8183 Overview
CVE-2025-8183 is a NULL pointer dereference vulnerability [CWE-476] in µD3TN, an open-source Delay-Tolerant Networking (DTN) implementation maintained by D3TN GmbH. The flaw allows a remote, unauthenticated attacker to send a Bundle Protocol bundle containing a non-singleton destination Endpoint Identifier (EID), which triggers a NULL dereference in the receiving daemon. The result is a reliable denial-of-service condition that crashes the µD3TN process. The vulnerability affects µD3TN version 0.14.3 and requires no privileges or user interaction to exploit.
Critical Impact
Remote attackers can reliably crash µD3TN nodes by transmitting a single crafted bundle, disrupting DTN-based communication links.
Affected Products
- D3TN µD3TN version 0.14.3
- CPE: cpe:2.3:a:d3tn:ud3tn:0.14.3
- Deployments using µD3TN for Bundle Protocol routing
Discovery Timeline
- 2025-07-25 - CVE-2025-8183 published to NVD
- 2025-08-11 - Last updated in NVD database
Technical Details for CVE-2025-8183
Vulnerability Analysis
The vulnerability resides in µD3TN's Bundle Protocol processing logic. µD3TN implements RFC 9171 Bundle Protocol version 7, where each bundle carries a destination Endpoint Identifier. EIDs may be either singleton (referencing a single node) or non-singleton (referencing a multicast or group destination). The destination handling code path assumes a singleton EID and dereferences a pointer that remains NULL when a non-singleton EID is supplied. The unhandled NULL dereference terminates the µD3TN process, breaking any bundle forwarding, custody transfer, or convergence-layer sessions hosted by the node.
Root Cause
The root cause is missing input validation on the destination EID type before pointer dereference. The code path for non-singleton EIDs was not fully implemented or guarded, leaving a structure pointer uninitialized. When the bundle dispatcher attempts to resolve the destination, it accesses fields through the NULL pointer, raising SIGSEGV. Detailed analysis is available in the GitLab Issue Discussion.
Attack Vector
An attacker reaches the vulnerable code over any configured convergence layer, including TCPCL, MTCP, or UDP. The attacker connects to the µD3TN listening socket and transmits a syntactically valid bundle whose primary block sets the destination EID as non-singleton. No authentication is required because Bundle Protocol nodes commonly accept bundles from peers without prior credential exchange. A single malformed bundle is sufficient to terminate the daemon, and the attack can be repeated whenever the operator restarts the service.
The vulnerability mechanism is described in the upstream issue tracker. Refer to the GitLab Issue Discussion for technical details rather than attempting to reconstruct exploit code.
Detection Methods for CVE-2025-8183
Indicators of Compromise
- Unexpected µD3TN process termination with SIGSEGV in system logs or core dumps
- Repeated service restarts of ud3tn shortly after inbound bundle traffic
- Inbound bundles whose primary block flags indicate a non-singleton destination EID
Detection Strategies
- Inspect convergence-layer traffic for bundles where the primary block "destination is singleton" flag is unset and correlate with subsequent process crashes.
- Monitor host telemetry for abnormal exit codes on the ud3tn binary, particularly segmentation faults occurring near peer connection events.
- Enable verbose µD3TN logging at startup to capture the last bundle headers processed before termination.
Monitoring Recommendations
- Configure host-based monitoring to alert on ud3tn service restarts and unclean exits.
- Forward µD3TN logs and crash artifacts to a central SIEM for correlation across nodes.
- Track the source addresses of peers whose transmitted bundles immediately precede daemon crashes.
How to Mitigate CVE-2025-8183
Immediate Actions Required
- Inventory all hosts running µD3TN 0.14.3 and prioritize those exposed to untrusted networks.
- Restrict convergence-layer listening sockets to trusted peer addresses using firewall rules or per-CLA allowlists.
- Increase log retention and crash-dump collection on µD3TN nodes until a fixed release is deployed.
Patch Information
At the time of NVD publication, no fixed version was listed in the advisory. Operators should track the GitLab Issue Discussion for the upstream fix and upgrade to a release that adds validation for non-singleton destination EIDs.
Workarounds
- Block inbound Bundle Protocol traffic from untrusted sources at the network perimeter.
- Place µD3TN behind authenticated convergence layers or VPN tunnels to limit who can transmit bundles.
- Use a process supervisor such as systemd with rate-limited automatic restart to reduce downtime if the daemon is crashed.
# Example systemd hardening for the ud3tn service
[Service]
Restart=on-failure
RestartSec=5s
StartLimitBurst=5
StartLimitIntervalSec=60
# Limit network exposure to trusted peers via firewall
# iptables -A INPUT -p tcp --dport 4556 -s 10.0.0.0/24 -j ACCEPT
# iptables -A INPUT -p tcp --dport 4556 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
