HIGHVulnerability
Verified
Global
NVD HIGH: CVE-2026-33661 — Pay is an open-source payment SDK extension package for various Chinese payment ...
Thursday, March 26, 2026 at 10:16 PM UTC·Source: NIST NVD
Updated: Thursday, April 2, 2026 at 05:46 PM UTC
Executive Summary
Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the `verify_wechat_sign()` function in `src/Functions.php` unconditionally skips all signature verification when the PSR-7 request reports `localhost` as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a `Host: localhos
Analysis
Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the `verify_wechat_sign()` function in `src/Functions.php` unconditionally skips all signature verification when the PSR-7 request reports `localhost` as the host. An attacker can exploit this by sending a crafted HTTP request to the WeChat Pay callback endpoint with a `Host: localhost` header, bypassing the RSA signature check entirely. This allows forging fake WeChat Pay payment success notifications, potentially causing applications to mark orders as paid without actual payment. Version 3.7.20 fixes the issue.
CVSS Score: 8.6. Published: 2026-03-26T22:16:29.560.