One Packet Can Crash OT Servers in Industrial Sectors

Security researchers at Ridge Security have disclosed a zero-day flaw in TDengine, an open-source time-series database widely deployed across manufacturing, energy, automotive and IoT environments, with over 730,000 instances reportedly in use at companies including Siemens, McDonald's, Sinopec and NavInfo. Tracked as CVE-2026-42542 (CVSS 7.5), the bug is an integer-underflow issue in TDengine's pre-authentication message handling on its default RPC port 6030, allowing an attacker with network access to crash the server by sending just one malformed packet—no credentials or session required. The flaw affects versions 3.4.0.0 through 3.4.1.5 and has been fixed in 3.4.1.6; while no in-the-wild exploitation or public exploit code has surfaced yet, Ridge Security built its own working proof-of-concept and warns that reproducing the bug would take hours rather than weeks. Because losing the database can mean losing visibility into industrial equipment and telemetry, the company urges affected organizations to update promptly or at least limit exposure to port 6030.