A high-severity vulnerability in TDengine, an open-source time-series database used across manufacturing, energy, automotive, and IoT environments, can let an unauthenticated attacker crash a vulnerable server with a single specially crafted network packet. The bug, tracked as CVE-2026-42542, was discovered by researchers at Ridge Security and has been fixed by TDengine in version 3.4.1.6. Operators who have not yet upgraded remain exposed, and the impact in industrial settings can reach well beyond a normal IT outage.<\/p>\n
TDengine stores and analyzes large volumes of time-stamped data, including sensor readings, industrial equipment telemetry, and application and infrastructure performance metrics. The project says more than 730,000 instances are currently running across organizations ranging from startups to large multinationals, with named customers including Siemens, McDonald’s, Sinopec, and NavInfo.<\/p>\n
The flaw is an integer-underflow bug in TDengine’s pre-authentication message parsing, meaning it triggers while the server is still processing the initial request from a client, before any credentials are checked. An integer underflow happens when a calculation produces a value smaller than the system can represent. Instead of failing, the value can wrap around to a very large number, which attackers can use to bypass checks, corrupt data, or crash the program.<\/p>\n
CVE-2026-42542 affects TDengine versions 3.4.0.0 through 3.4.1.5 and carries a CVSS score of 7.5. Ridge Security describes the fix as a three-line change guarding a subtraction, in a function that runs before authentication, on a port that in many networks is reachable from too many places.<\/p>\n
TDengine’s RPC service listens on TCP port 6030 by default, which makes exposed instances easy to find through routine network scanning. An attacker who already has a foothold on an internal network can locate TDengine systems through standard reconnaissance, and the database’s default port is straightforward to identify from the outside as well.<\/p>\n
Once an attacker finds an instance, reproducing the crash requires little effort. The bug can be triggered with a single malformed network packet, without credentials and without an established session. The main challenge for an attacker is determining whether a particular instance has been patched, but because the exploit is cheap to attempt, a scanner can simply test every instance it finds.<\/p>\n
The confirmed impact is a denial-of-service condition that remotely crashes the database. In environments that depend on TDengine for operational monitoring, losing access to the data can have consequences beyond a conventional IT outage. Telemetry generated during an outage may go unrecorded, creating gaps in historical records, and operations teams can lose visibility into the systems and processes they rely on to detect problems. Dashboards, analytics, anomaly detection, and other applications that draw from the database may lose their data source.<\/p>\n
Ridge Security identified the flaw while testing open-source applications used in IoT and operational technology environments that traditional IT security tools often overlook. The sectors that lean on TDengine for sensor and equipment data, including manufacturing, energy, utilities, connected vehicles, and broader IoT, depend on the database to keep an accurate, real-time picture of operations. A crash of that database can mean losing visibility into equipment and processes at exactly the moment a problem needs to be detected.<\/p>\n
Industrial environments also tend to have limited maintenance windows, and TDengine may be bundled inside a larger appliance or solution. As a result, not every organization will be able to patch immediately, and some may not realize they are running an affected version at all.<\/p>\n
Ridge Security recommends that organizations using TDengine apply the vendor’s security update as soon as practical, moving to version 3.4.1.6 or later. The vendor published its security advisory on June 4 for customers, and the patch has been available since April, so the fix has been out for months.<\/p>\n
For organizations that cannot upgrade immediately, the recommended compensating control is reducing network exposure to the affected service. The specific step is to restrict access to TCP port 6030, TDengine’s default RPC port, so that the database is not reachable from networks where it does not need to be.<\/p>\n
So far, there is no evidence of attacks targeting the vulnerability in the wild, and no public exploit code has appeared. Ridge Security has developed a proof-of-concept exploit but has chosen not to disclose it publicly. That situation can change quickly given how cheap the attack is to attempt, which is why patching and exposure reduction both matter.<\/p>\n
CVE-2026-42542 is a high-severity integer-underflow vulnerability in the TDengine time-series database, affecting versions 3.4.0.0 through 3.4.1.5. It allows an unauthenticated attacker with network access to TCP port 6030 to crash the server with a single crafted packet, causing a denial-of-service condition. The bug has a CVSS score of 7.5 and was fixed in TDengine version 3.4.1.6.<\/p>\n
Industrial telemetry, IoT, energy and utilities, connected vehicles, and other operational environments face the highest risk because they depend on TDengine for time-series data from sensors and equipment. Losing the database in these settings can mean losing visibility into equipment and operations and creating gaps in historical telemetry data.<\/p>\n
Upgrade to TDengine version 3.4.1.6 or later as soon as possible, since the patch has been available since April. When an immediate upgrade is not possible, restrict network access to TCP port 6030, the database’s default RPC port, to reduce exposure of the affected service.<\/p>\n