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

> Unauthenticated remote attackers can crash the TDengine server via a crafted RPC packet due to an integer underflow, requiring an upgrade to fix.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jun 2026
- **Updated:** 11 Jun 2026
- **Also known as:** GHSA-vg95-j2hf-hvjx

## What is CVE-2026-42542?

CVE-2026-42542 is a high-severity vulnerability in taosdata TDengine, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-42542?

It affects 1 product.


Products: Tdengine Tdengine.

## How do I fix CVE-2026-42542?

No fix has been published for CVE-2026-42542 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42542 being exploited?

There is no known exploitation of CVE-2026-42542 in the wild and no public exploit code.

## Other vulnerabilities in taosdata TDengine

- [CVE-2023-38502](https://insights.sbomify.com/CVE-2023-38502/): TDengine Database Denial-of-Service (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42542 and fix it if it is affected.

What it is: CVE-2026-42542 is a high-severity vulnerability in taosdata TDengine, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42542 in the wild and no public exploit code.

Affected product: taosdata TDengine. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42542/ (Markdown: https://insights.sbomify.com/CVE-2026-42542/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42542
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42542
- OSV: https://osv.dev/vulnerability/CVE-2026-42542

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42542/
Summaries are generated and may contain mistakes; the official description above is the record.