Description

MQTT credentials and control traffic are transmitted in cleartext, exposing sensitive information to network-level attackers. This may enable unauthorized device impersonation and disruption of messaging functions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-28T00:18:08.650Z",
  "pubdate": "2026-08-28T00:18:08.650Z",
  "executiveSummary": "The vulnerability involves the transmission of MQTT protocol credentials and control traffic over unencrypted network channels.\nThis lack of transport layer security (TLS) results in sensitive information disclosure, specifically exposing authentication tokens and sensitive operational data to passive and active network-level adversaries.\nAffected systems are those utilizing MQTT without enforcing encrypted communication tunnels, such as TLS or SSL.\nThe primary risk implication is the compromise of device integrity and the integrity of the messaging infrastructure.\nAttackers positioned within the same network segment can leverage packet sniffing techniques to capture credentials, subsequently facilitating unauthorized device impersonation.\nThe threat vector allows for the disruption of messaging functions, potential command injection, and unauthorized data exfiltration.\nNo complex exploitation requirements exist, as the vulnerability is inherent to the insecure configuration of the communication channel, requiring only network visibility to the traffic stream.",
  "technicalDetails": "The root cause of this vulnerability is the absence of TLS/SSL encryption for MQTT traffic, which defaults to cleartext communication over TCP ports 1883. Because MQTT is a lightweight messaging protocol frequently used in IoT environments, the lack of cryptographic wrappers allows for trivial interception of the protocol's control packets.\nDuring the MQTT CONNECT handshake, the client transmits a packet containing the ClientID, Username, and Password fields. In an unencrypted state, these fields are transmitted as plaintext strings within the TCP payload. An attacker performing a man-in-the-middle (MITM) attack or simply sniffing traffic on a shared network segment can utilize tools such as Wireshark or tcpdump to capture these frames, extract the credentials, and store them for later use.\nThe attack flow proceeds as follows: First, the attacker gains network-level access to the communication path between the MQTT client and the broker. Second, the attacker employs packet capture software to monitor traffic directed at the broker's IP address. Third, upon detecting a TCP handshake and subsequent MQTT connection, the attacker filters for the CONNECT packet to extract the authentication payload. Fourth, having obtained valid credentials, the attacker can disconnect the legitimate client by sending a malicious disconnect signal or by assuming the identity of the client to the broker.\nOnce impersonation is successful, the attacker gains the ability to subscribe to sensitive MQTT topics or publish malicious messages to the broker. This effectively grants the attacker control over the messaging functions of the affected IoT ecosystem. The post-exploitation impact includes the capability to issue unauthorized commands to end-devices, intercept data telemetry, or trigger denial-of-service (DoS) conditions by flooding the broker with malformed or excessive control traffic.\nThis vulnerability is classified as a failure of security configuration and lack of transport encryption. The vulnerable component is the MQTT communication channel itself, which fails to enforce secure transport protocols. The exposure is network-wide, and no specific privilege is required beyond the ability to capture traffic. The threat is persistent as long as cleartext communication remains enabled, and it poses a severe risk to the confidentiality and availability of the entire messaging infrastructure."
}