CVE-2026-93652: µD3TN TCPCLv3 Integer Overflow DoS Vulnerability

CVE-2026-93652 Overview

CVE-2026-93652 is an integer overflow vulnerability in µD3TN v0.15.0, a delay-tolerant networking (DTN) implementation. The flaw resides in the TCP Convergence Layer version 3 (TCPCLv3) handshake logic. An integer overflow during handshake processing leads to a heap overflow condition. Remote attackers can reliably trigger a denial-of-service (DoS) condition without authentication or user interaction. The vulnerability is tracked under CWE-190: Integer Overflow or Wraparound.

Critical Impact
Unauthenticated network attackers can reliably crash µD3TN v0.15.0 instances by sending crafted TCPCLv3 handshake traffic, disrupting delay-tolerant network communications.

Affected Products

µD3TN v0.15.0
TCPCLv3 convergence layer component
Delay-tolerant networking deployments using affected versions

Discovery Timeline

2026-09-18 - CVE-2026-93652 published to NVD
2026-09-18 - Last updated in NVD database

Technical Details for CVE-2026-93652

Vulnerability Analysis

The vulnerability affects the TCPCLv3 handshake implementation in µD3TN v0.15.0. µD3TN is a lightweight, portable implementation of Bundle Protocol (BP) used in delay-tolerant networks including space and constrained environments. During the initial TCPCLv3 handshake, the code performs arithmetic on a length or size value derived from attacker-controlled input. The arithmetic wraps around due to insufficient bounds checking, producing a small allocation size followed by a larger copy operation. This mismatch corrupts adjacent heap memory and causes the process to crash. Further technical analysis is available in the GitLab Work Item Analysis.

Root Cause

The root cause is an unchecked integer arithmetic operation on a size field parsed from the TCPCLv3 handshake message. When the computed value exceeds the maximum representable integer, it wraps to a smaller value. The subsequent memory allocation uses the wrapped value, but the copy operation uses the original attacker-supplied length, producing a heap overflow [CWE-190].

Attack Vector

An attacker requires network reachability to the µD3TN TCPCLv3 listener. No authentication or user interaction is required. The attacker connects to the TCPCLv3 port and transmits a crafted handshake message containing values that trigger the integer overflow. The heap overflow reliably crashes the process, producing a denial-of-service condition. Confidentiality and integrity are not directly impacted, but availability is fully compromised.

No verified public exploit code is available. Refer to the GitLab Work Item Analysis for reproduction details.

Detection Methods for CVE-2026-93652

Indicators of Compromise

Unexpected termination or crash logs from ud3tn processes shortly after inbound TCPCLv3 connections.
Core dumps or segmentation fault entries in system logs correlated with TCPCLv3 listener ports.
Repeated short-lived TCP connections to the µD3TN TCPCLv3 port from unfamiliar sources.

Detection Strategies

Monitor network traffic to TCPCLv3 listener ports for anomalously large or malformed handshake length fields.
Deploy process-monitoring rules that alert on ud3tn daemon crashes and automatic restarts.
Correlate service outages of µD3TN nodes with inbound connection metadata to identify targeted DoS attempts.

Monitoring Recommendations

Enable verbose logging on µD3TN nodes to capture handshake parsing errors and connection metadata.
Forward host telemetry from DTN nodes into a centralized SIEM for correlation with network flow data.
Track service availability metrics for µD3TN endpoints to detect repeated crash-restart cycles.

How to Mitigate CVE-2026-93652

Immediate Actions Required

Identify all µD3TN v0.15.0 deployments and inventory exposed TCPCLv3 listener endpoints.
Restrict network access to TCPCLv3 ports using firewall rules limiting inbound connections to trusted DTN peers.
Monitor upstream µD3TN releases and apply the fixed version once available from the vendor.

Patch Information

At time of publication, refer to the upstream project tracker at the GitLab Work Item Analysis for current patch status. Upgrade to a version newer than v0.15.0 once the maintainers publish a fix that adds bounds checking to the TCPCLv3 handshake length processing.

Workarounds

Place µD3TN nodes behind a network filter that only permits handshake traffic from authenticated peer addresses.
Disable the TCPCLv3 convergence layer if it is not required, and use an alternative convergence layer such as MTCP.
Deploy service supervision tooling to automatically restart crashed ud3tn processes and preserve availability during triage.

bash

# Configuration example: restrict TCPCLv3 access with iptables
# Replace <trusted_peer_ip> and <tcpclv3_port> with your environment values
iptables -A INPUT -p tcp --dport <tcpclv3_port> -s <trusted_peer_ip> -j ACCEPT
iptables -A INPUT -p tcp --dport <tcpclv3_port> -j DROP