Description

Unauthenticated Cross Site Scripting (XSS) in NextGEN Gallery <= 4.2.3 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-08-06T15:16:52.830Z",
  "pubdate": "2026-08-06T15:16:52.830Z",
  "executiveSummary": "An unauthenticated Cross-Site Scripting (XSS) vulnerability has been identified in the NextGEN Gallery plugin affecting versions 4.2.3 and prior. This security flaw enables remote attackers to inject malicious client-side scripts, typically JavaScript, into web pages rendered to unsuspecting users visiting the compromised WordPress site. The primary impact of this vulnerability includes session hijacking, credential theft, defacement, and the potential execution of unauthorized actions within the context of a victim's browser session. The affected systems are WordPress installations utilizing vulnerable versions of the NextGEN Gallery plugin. The risk implications are severe due to the unauthenticated nature of the exploit vector, meaning any remote attacker without prior credentials or system access can initiate the attack sequence. Exploitation requires no privileged access, lowering the barrier for malicious actors to compromise site integrity and user trust. Remediation necessitates immediate upgrading of the NextGEN Gallery plugin beyond the vulnerable version threshold once a patched release is made available by the vendor.",
  "technicalDetails": "The vulnerability resides within the request handling and parameter rendering logic of the NextGEN Gallery plugin for versions 4.2.3 and below. The root cause stems from insufficient input sanitization and inadequate output encoding of user-supplied data before it is reflected back in the Document Object Model (DOM). Specifically, HTTP requests containing malicious payloads crafted with HTML and JavaScript elements fail to undergo rigorous validation processes within the affected components. Because the vulnerability is unauthenticated, attackers can transmit crafted requests directly over the network without requiring any prior authentication tokens or low-level privileges. The network exposure is public-facing, allowing external threat actors to target the application layer directly. The attack flow begins when an attacker crafts a malicious URL or HTTP request containing script payloads designed to bypass basic filters. Upon submission, the vulnerable component processes the unsanitized input and incorporates it directly into the Hypertext Markup Language (HTML) response sent to the client browser. When a victim accesses the maliciously crafted link or views the compromised page, the browser interprets the injected payload as legitimate application code rather than inert text data. The payload behavior executes within the security context of the victim's session, possessing the capability to access document properties, manipulate DOM elements, intercept sensitive cookies, and perform unauthorized asynchronous requests on behalf of the user. Post-exploitation impact varies depending on the targeted user role; if an administrative user falls victim to the injected payload, the attacker can leverage the resulting privileges to create new rogue administrator accounts, modify core application files, or deploy persistent malware across the hosting server environment."
}