CVE-2026-6559: Wavlink WL-WN579A3 login.cgi sub_401F80 cross site scripting

Vulnerability summary

CVE-2026-6559 is a medium (CVSS 5.3) Cross-site Scripting vulnerability in wavlink wl-wn579a3_firmware. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.9% of scored vulnerabilities.

Timeline

1. 19-04-2026
   PublishedVulnerability first disclosed.
2. 20-04-2026
   Last modifiedVulnerability information updated.

Description

A weakness has been identified in Wavlink WL-WN579A3 220323. This affects the function sub_401F80 of the file /cgi-bin/login.cgi. This manipulation of the argument Hostname causes cross site scripting. Remote exploitation of the attack is possible. Upgrading the affected component is recommended. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.