CVE-2026-86414
Published Oct 20, 2026
Modified Oct 22, 2026
Description
An HTTP proxy can trick libcurl into sending the origin's credentials (Basic password, or a Negotiate/Kerberos ticket) to the proxy itself, by answering the `CONNECT` tunnel request with 401 `WWW-Authenticate:` instead of the expected 407 `Proxy-Authenticate:`.
Is your site exposed to CVE-2026-86414?
Run a free security scan — no signup, results in seconds.
EPSS — Exploit Prediction
0.0068
Probability of exploitation
0.53%
Percentile rank
EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.
References
Frequently Asked Questions
What is CVE-2026-86414? +
An HTTP proxy can trick libcurl into sending the origin's credentials (Basic
password, or a Negotiate/Kerberos ticket) to the proxy itself, by answering
the `CONNECT` tunnel request with 401 `WWW-Authenticate:` instead of the
expected 407 `Proxy-Authenticate:`.
How do I check if I'm vulnerable to CVE-2026-86414? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.
