CVE-2026-33661 WeChat Pay callback signature verification bypassed when Host header is localhost

Pay is an open-source payment SDK extension package for various Chinese payment services. Prior to version 3.7.20, the verifywechatsign 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...

WeChat Pay callback signature verification bypassed when Host header is localhost

Summary The verifywechatsign 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,...

User Impersonation

Overview Affected versions of this package are vulnerable to User Impersonation via the verifywechatsign function. An attacker can cause unauthorized order status changes by sending a crafted HTTP request with a Host: localhost header, which bypasses signature verification and allows forging...