Description

Unauthenticated Cross Site Scripting (XSS) in LeadConnector <= 4.0.5 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-08-31T21:17:50.567Z",
  "pubdate": "2026-08-31T21:17:50.567Z",
  "executiveSummary": "LeadConnector versions 4.0.5 and below are susceptible to an unauthenticated Cross-Site Scripting (XSS) vulnerability.\nThis flaw allows remote, unauthenticated attackers to inject arbitrary malicious scripts into web pages viewed by other users within the application environment.\nThe vulnerability stems from improper neutralization of user-supplied input before it is rendered by the web browser.\nImpact includes the potential for session hijacking, theft of sensitive authentication tokens, unauthorized actions performed on behalf of the victim, and the defacement of the application interface.\nBecause the vulnerability is exploitable without authentication, the attack surface is significantly expanded, allowing any network-adjacent or external actor to target users.\nSuccessful exploitation poses a critical risk to data confidentiality and integrity, as malicious scripts can execute within the context of the victim's session, bypassing standard security controls if not mitigated correctly.\nOrganizations relying on affected versions of LeadConnector are advised to prioritize remediation to prevent credential harvesting or secondary malicious activities facilitated by this browser-based execution flaw.",
  "technicalDetails": "The vulnerability resides within the input processing and output rendering logic of the LeadConnector application, specifically affecting versions 4.0.5 and lower.\nThe root cause is an inadequate implementation of input sanitization or output encoding mechanisms for user-supplied data transmitted to the browser.\nAttackers can leverage this flaw by supplying crafted payloads containing JavaScript tags or event handlers within input fields or URL parameters that the application subsequently reflects to the client-side.\nBecause the application fails to properly escape or sanitize these inputs, the browser interprets the injected data as legitimate executable code rather than plain text.\nThe exploitation process typically follows a clear flow: First, an attacker identifies an injection vector—such as a search field, profile parameter, or URL variable—that is improperly handled by the application server. Second, the attacker crafts a malicious JavaScript payload designed to trigger a specific action, such as stealing document.cookie data or performing a DOM manipulation. Third, the attacker delivers this payload to a victim, often via a crafted URL or a compromised page. Finally, when the victim accesses the affected page, their browser executes the embedded script within the context of the origin, granting the attacker access to the user's session data.\nThe scope of this vulnerability is broad due to its unauthenticated nature, meaning the attacker does not require a valid user account to trigger the execution of the payload. The affected component is likely a server-side module that constructs HTML responses dynamically without validating the content of the parameters being inserted.\nPost-exploitation impact is severe, as the attacker can manipulate the Document Object Model (DOM) of the application. This allows for the exfiltration of sensitive information, such as session cookies, which can be sent to an attacker-controlled listener. Furthermore, the attacker can silently perform unauthorized actions within the LeadConnector interface by executing administrative functions through the victim's authenticated session, effectively performing a Cross-Site Request Forgery (CSRF) in addition to the XSS payload. The vulnerability relies solely on the browser's trust in the origin; once the script is executed, the browser enforces no further restrictions on the malicious code's ability to access data belonging to the application's origin."
}