CVE-2025-0746: Thesamur Embedai XSS Vulnerability

CVE-2025-0746 Overview

CVE-2025-0746 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting EmbedAI version 2.1 and earlier releases. The flaw resides in the /embedai/users/show/ endpoint, which fails to sanitize user-supplied input reflected into the response. An authenticated attacker can craft a malicious URL containing JavaScript payloads that execute in a victim's browser when the link is opened. Successful exploitation runs in the context of the target user's session and can lead to session token theft, unauthorized actions, and content manipulation within the EmbedAI application.

Critical Impact
Authenticated attackers can execute arbitrary JavaScript in victim browsers by delivering crafted URLs targeting the vulnerable /embedai/users/show/ endpoint, enabling session hijacking and impersonation within EmbedAI.

Affected Products

Thesamur EmbedAI version 2.1
Thesamur EmbedAI versions prior to 2.1
Deployments exposing the /embedai/users/show/ route to authenticated users

Discovery Timeline

2025-01-30 - CVE-2025-0746 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-0746

Vulnerability Analysis

The vulnerability is a Reflected Cross-Site Scripting flaw categorized under [CWE-79]: Improper Neutralization of Input During Web Page Generation. EmbedAI takes path segment input passed to the /embedai/users/show/<value> endpoint and reflects it in the rendered HTML response without adequate output encoding.

Because the payload is embedded directly into the response body, a browser parses attacker-controlled markup as executable script. Exploitation requires authentication and user interaction, since the victim must click or otherwise open the crafted URL. Once triggered, the injected script executes in the same origin as EmbedAI, granting the attacker access to session cookies, DOM state, and any privileged actions the victim can perform.

Root Cause

The root cause is missing input sanitization and output encoding on the <SCRIPT> path parameter accepted by the /embedai/users/show/ route. The application concatenates or interpolates the raw value into HTML output rather than applying context-aware escaping. This allows tags such as <script> or event-handler attributes to reach the browser intact.

Attack Vector

An authenticated attacker constructs a URL targeting the vulnerable endpoint with a JavaScript payload appended to the users/show/ path. The attacker then delivers the URL via phishing, chat, or another social engineering channel to a logged-in EmbedAI user. When the victim opens the link, the browser executes the reflected payload under the EmbedAI origin.

Because the CVSS scope is changed, injected script can affect resources beyond the vulnerable component, including cross-origin data accessible to the victim's session. Refer to the INCIBE Notice on Multiple Vulnerabilities for additional technical detail.

Detection Methods for CVE-2025-0746

Indicators of Compromise

HTTP requests to /embedai/users/show/ containing URL-encoded <script>, onerror=, onload=, or javascript: substrings
Web server or proxy logs showing unusually long path segments under the users/show/ route
Referrer headers indicating externally hosted links redirecting authenticated users into EmbedAI
Unexpected outbound requests from user browsers to attacker-controlled domains shortly after EmbedAI access

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the /embedai/users/show/ path for script tags, event handlers, and encoded angle brackets
Correlate authentication events with anomalous request patterns targeting the vulnerable endpoint
Review browser telemetry for script execution originating from EmbedAI-hosted pages with suspicious inline payloads

Monitoring Recommendations

Enable verbose HTTP logging on EmbedAI reverse proxies to capture full request URIs and referrers
Alert on repeated 200 responses to /embedai/users/show/ requests containing angle brackets or percent-encoded XSS primitives
Monitor for session anomalies such as concurrent logins, sudden privilege changes, or credential resets tied to EmbedAI accounts

How to Mitigate CVE-2025-0746

Immediate Actions Required

Restrict access to the /embedai/users/show/ endpoint until a fixed version is deployed
Apply WAF signatures that block XSS payloads on EmbedAI request paths
Enforce a strict Content Security Policy (CSP) to limit inline script execution in EmbedAI responses
Notify EmbedAI users to avoid clicking untrusted links referencing the application

Patch Information

No vendor patch URL is listed in the enriched CVE data. Administrators should consult the INCIBE Notice on Multiple Vulnerabilities and the EmbedAI project repository for the latest fixed release. Upgrade beyond version 2.1 once a remediated build is published by the vendor.

Workarounds

Place EmbedAI behind a reverse proxy that rejects request paths containing <, >, or %3C/%3E sequences under /embedai/users/show/
Configure browsers and application responses with X-XSS-Protection, X-Content-Type-Options: nosniff, and a restrictive CSP header
Shorten session lifetimes and require re-authentication for sensitive operations to reduce the value of stolen tokens
Disable the affected endpoint through routing rules if it is not required for business operations

bash

# Example NGINX rule to block XSS payloads on the vulnerable path
location ~* ^/embedai/users/show/ {
    if ($request_uri ~* "(<|%3C|script|onerror|onload|javascript:)") {
        return 403;
    }
    proxy_pass http://embedai_backend;
}