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.

Pay is a payments engine for Ruby on Rails 6.0 and higher. In versions prior to 6.3.2 a payments info page of Pay is susceptible to reflected Cross-site scripting. An attacker could create a working URL that renders a javascript link to a user on a Rails application that integrates Pay. This URL could be distributed via email to specifically target certain individuals. If the targeted application contains a functionality to submit user-generated content (such as comments) the attacker could even distribute the URL using that functionality. This has been patched in version 6.3.2 and above. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Solana Pay is a protocol and set of reference implementations that enable developers to incorporate decentralized payments into their apps and services. When a Solana Pay transaction is located using a reference key, it may be checked to represent a transfer of the desired amount to the recipient, using the supplied `validateTransfer` function. An edge case regarding this mechanism could cause the validation logic to validate multiple transfers. This issue has been patched as of version `0.2.1`. Users of the Solana Pay SDK should upgrade to it. There are no known workarounds for this issue.

Improper export of Android application components vulnerability in Samsung Pay (India only) prior to version 4.1.77 allows attacker to access Bill Pay and Recharge menu without authentication.

Improper check or handling of exception conditions vulnerability in Samsung Pay (US only) prior to version 4.0.65 allows attacker to use NFC without user recognition.