Description

Unauthenticated Cross Site Scripting (XSS) in WP Multilang <= 2.4.31 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-08-18T15:17:02.790Z",
  "pubdate": "2026-08-18T15:17:02.790Z",
  "executiveSummary": "An unauthenticated Cross-Site Scripting (XSS) vulnerability exists in the WP Multilang plugin for WordPress, specifically affecting versions up to 2.4.31. This security flaw allows remote, unauthenticated attackers to inject malicious client-side scripts, typically JavaScript or HTML, into web pages rendered by the application. The primary impact of this vulnerability includes unauthorized actions performed on behalf of authenticated users, session hijacking, credential theft, and defacement of the affected WordPress site. The vulnerability resides within the request handling and parameter rendering logic of the plugin, which fails to adequately sanitize or escape user-supplied input before reflecting it back in the HTTP response. Because exploitation requires no prior authentication or administrative privileges, external threat actors can target vulnerable systems over the network with minimal friction. Successful exploitation relies on the victim interacting with a maliciously crafted URL or input parameter processed by the vulnerable plugin component. Immediate remediation requires updating the WP Multilang plugin beyond version 2.4.31 or applying official vendor patches to enforce proper output encoding and input validation mechanisms across all affected endpoints.",
  "technicalDetails": "The vulnerability is classified as a Reflected Cross-Site Scripting (XSS) flaw stemming from insufficient input sanitization and output encoding within the WP Multilang plugin <= 2.4.31. The root cause lies in the application's failure to properly validate and sanitize HTTP request parameters before reflecting them into the Document Object Model (DOM) of the generated HTML response. Attackers can exploit this flaw by crafting malicious URLs containing JavaScript payloads injected into vulnerable parameters processed by the plugin. When an unauthenticated user or an administrator clicks or is redirected to the maliciously crafted URL, the web server processes the request and includes the unsanitized payload within the application response. Upon receiving the response, the victim's browser parses and executes the injected script within the context of the vulnerable origin. Because the script executes in the browser of the client, it gains access to sensitive session tokens, cookies, and local storage associated with the WordPress instance. The attack vector is strictly network-based, requiring HTTP/HTTPS access to the target WordPress installation. No authentication or specific user privileges are required to deliver the payload, making it an unauthenticated attack vector. Post-exploitation impact depends on the privileges of the user targeted by the exploit; if an administrative user falls victim to the attack, the malicious script can execute privileged actions such as creating rogue administrator accounts, modifying plugin files, or deploying web shells. The vulnerable component fails to implement context-aware output encoding functions such as esc_html(), esc_attr(), or equivalent sanitization routines necessary to neutralize HTML and JavaScript context switches."
}