request-filtering-agent versions 1.x.x and earlier contain a vulnerability where HTTPS requests to 127.0.0.1 bypass IP address filtering, while HTTP requests are correctly blocked.
Impact:
Vulnerable patterns (requests that should be blocked but are allowed):
https://127.0.0.1This vulnerability primarily affects services using self-signed certificates on 127.0.0.1.
Not affected (correctly blocked in all versions):
This allows attackers to potentially access internal HTTPS services running on localhost, bypassing the library's SSRF protection. The vulnerability is particularly dangerous when the application accepts user-controlled URLs and internal services are only protected by network-level restrictions.
This vulnerability has been fixed in request-filtering-agent version 2.0.0. Users should upgrade to version 2.0.0 or later.
Root Cause:The HTTPS agent fails to validate direct IP addresses like https://127.0.0.1 during TLS connection setup, allowing them to bypass the security filter.
Details: https://github.com/azu/request-filtering-agent-https127-test
Thanks Luca
{
"cwe_ids": [
"CWE-918"
],
"github_reviewed": true,
"github_reviewed_at": "2025-08-25T21:48:01Z",
"nvd_published_at": "2025-08-25T22:15:33Z",
"severity": "MODERATE"
}