Can attackers spoof signatures in Sipay OpenCart Virtual POS versions below 26.9.1?
Sipay’s OpenCart Virtual POS module contains a high-severity signature validation error allowing spoofing in versions prior to 26.9.1.
Key points
- The flaw is classified as critical with a CVSS score of 9.8.
- It affects Sipay OpenCart Virtual POS Module versions from 26.8.2 up to, but not including, 26.9.1.
- The vulnerability enables signature spoofing through improper cryptographic validation.
Sipay Electronic Money and Payment Services Inc. has a critical vulnerability in its OpenCart Virtual POS Module. The issue stems from improper verification of cryptographic signatures, which allows attackers to spoof signatures by bypassing validation checks. This flaw is tracked as CVE-2026-85531.
Root cause
The underlying weakness is identified as CWE-347, which relates to improper verification of cryptographic signatures. According to the National Vulnerability Database (NVD), the module fails to correctly validate the integrity of digital signatures. This lack of proper validation creates a gap where malicious actors can manipulate data without detection, effectively forging trust in the payment transaction process.
Attack path
An attacker exploiting this vulnerability can perform signature spoofing. By sending crafted requests that bypass the module’s validation logic, the attacker can alter transaction details or inject fraudulent data. Because the module does not rigorously verify the cryptographic signature, it accepts these tampered inputs as legitimate. This could lead to unauthorized transactions or data manipulation within the OpenCart environment.
Affected versions
The vulnerability impacts specific releases of the Sipay OpenCart Virtual POS Module. The affected range begins with version 26.8.2 and includes all subsequent versions prior to 26.9.1. Organizations running version 26.9.1 or later are not affected by this specific issue, as the fix is included in that release.
Mitigation
- Update the Sipay OpenCart Virtual POS Module to version 26.9.1 or later to resolve the signature verification flaw.
- Audit current OpenCart installations to identify the installed version of the Sipay module.
- Monitor transaction logs for anomalies that might indicate signature spoofing attempts.
- Ensure that all cryptographic validation processes are functioning as intended in the payment gateway.
What to do and how to stay safe: Sipay
- Inventory all e-commerce plugins and modules to determine if the Sipay OpenCart Virtual POS Module is installed.
- Check the current version number against the affected range (26.8.2 to pre-26.9.1).
- Apply the vendor update to version 26.9.1 as soon as possible to patch the vulnerability.
- Review recent transaction logs for any irregularities that could suggest exploitation before the patch was applied.
Step-by-step guide: Patch Testing Best Practices That Prevent Production Failures
General security guidance from the CloudSec Press newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-85531?
CVE-2026-85531 is a critical vulnerability in the Sipay OpenCart Virtual POS Module that allows signature spoofing due to improper cryptographic signature verification.
Which versions of the module are affected?
The vulnerability affects versions starting from 26.8.2 up to, but not including, version 26.9.1.
Is there a fix available?
Yes, the issue is resolved in version 26.9.1 of the Sipay OpenCart Virtual POS Module.
