CVE-2026-4765 Overview
CVE-2026-4765 is a stored Cross-Site Scripting (XSS) vulnerability affecting the RD Station Conversas chat application. The flaw exists in the name parameter during the chat initialization process, where user-supplied input is not properly sanitized before being stored and rendered. An attacker can inject arbitrary JavaScript that executes both in the victim's browser and in the browser of any support agent who joins the conversation. This second-order execution expands the attack surface beyond typical self-XSS scenarios, exposing internal operators to session theft, credential harvesting, and unauthorized actions within the application context. The vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation.
Critical Impact
Attackers can execute arbitrary JavaScript in the browsers of both customers and support agents, enabling session hijacking and impersonation within the RD Station Conversas platform.
Affected Products
- RD Station Conversas (Tallos Chat) — see the INCIBE advisory for specific versions
Discovery Timeline
- 2026-07-13 - CVE-2026-4765 published to NVD
- 2026-07-13 - Last updated in NVD database
Technical Details for CVE-2026-4765
Vulnerability Analysis
The vulnerability is a stored XSS flaw located in the chat initialization workflow of RD Station Conversas. When a user starts a new conversation, the application accepts the name parameter without adequate output encoding or input validation. The submitted value is persisted server-side and later rendered in the chat interface used by support agents and other participants.
Because the payload is stored, it triggers each time the conversation is loaded. When a support agent opens the conversation to respond, the injected JavaScript executes in the agent's authenticated session context. This transforms a client-facing input into a vector for internal compromise.
Exploitation requires user interaction from the victim who opens the conversation, but does not require authentication or elevated privileges from the attacker. The scope crosses trust boundaries because the attacker-controlled content executes within the operator-facing view of the application.
Root Cause
The root cause is improper neutralization of user input in the name parameter [CWE-79]. The application fails to sanitize or contextually encode the value before persisting it and before rendering it in HTML contexts consumed by other users of the platform.
Attack Vector
An unauthenticated attacker initiates a chat session with RD Station Conversas and supplies a crafted name value containing an HTML or JavaScript payload. The server stores the payload and delivers it to any support agent who subsequently opens the conversation. The malicious script then runs with the privileges of the agent's browser session, potentially exfiltrating tokens, cookies, or in-application data.
Refer to the INCIBE Security Advisory on XSS for additional technical detail on the vulnerable parameter and reproduction steps.
Detection Methods for CVE-2026-4765
Indicators of Compromise
- Chat records containing HTML tags such as <script>, <img onerror=>, <svg onload=>, or encoded variants within the name field of initialization requests.
- Outbound requests from support agent browsers to unknown external domains immediately after opening a customer conversation.
- Unexpected DOM modifications or JavaScript errors logged in agent workstation browsers when loading specific chat sessions.
Detection Strategies
- Inspect application logs and database entries for the name parameter containing characters such as <, >, or javascript: schemes.
- Deploy a Web Application Firewall (WAF) rule to flag XSS-typical payload signatures submitted to chat initialization endpoints.
- Correlate agent browser telemetry with chat access events to identify anomalous script execution tied to specific conversations.
Monitoring Recommendations
- Enable Content Security Policy (CSP) violation reporting to capture blocked inline script execution attempts in agent browsers.
- Monitor support agent sessions for unusual API calls, credential prompts, or session token access that follow chat interactions.
- Alert on any storage of unescaped HTML markup within chat metadata fields across the historical conversation database.
How to Mitigate CVE-2026-4765
Immediate Actions Required
- Contact RD Station support to confirm patch availability and apply any vendor-provided fix as soon as it is released.
- Review historical chat records for stored payloads and sanitize or purge affected entries before agents access them.
- Restrict agent browser sessions with strict CSP directives to limit the impact of any residual script execution.
Patch Information
At the time of publication, the INCIBE advisory is the authoritative source for remediation status. Confirm the current patched version directly with RD Station and apply updates to all instances of the Conversas chat integration.
Workarounds
- Implement server-side input validation that rejects HTML control characters in the name parameter of chat initialization requests.
- Apply contextual output encoding for all user-supplied fields rendered in the agent-facing chat interface.
- Deploy a WAF rule set targeting XSS payload patterns on the chat initialization endpoint until an official patch is applied.
- Train support agents to recognize and report unusual chat rendering behavior and to avoid interacting with suspicious conversations.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
