Reflected Cross-Site Scripting Vulnerability in Flow Payment Plugin for WordPress
CVE-2026-57857

5.1MEDIUM

Key Information:

Vendor

WordPress
Status
Flow Payment
Vendor
CVE Published:
18 July 2026

What is CVE-2026-57857?

The Flow Payment Plugin for WordPress, specifically version 3.0.8, is susceptible to a reflected cross-site scripting (XSS) vulnerability due to inadequate input sanitization and output escaping on the WooCommerce checkout page. When an order cancellation is processed, the error_message GET parameter is directly passed to the wc_add_notice() function without proper handling. As a result, an attacker can craft a malicious URL embedding a JavaScript payload in the error_message parameter. If a victim, who is currently engaged in a WooCommerce checkout session, clicks this link, the payload executes in the context of the victim's browser, potentially compromising their data and security.

Affected Version(s)

Flow Payment 0 <= 3.0.8

Flow Payment 0 <= 3.0.8

Flow Payment 3.0.9

References

https://www.flow.cl/
product
https://www.vulncheck.com/advisories/flow-payment-plugin-...
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Quarancle
.