CVE-2025-55123 Overview
CVE-2025-55123 is a stored cross-site scripting (XSS) vulnerability in Revive Adserver, an open-source ad management platform. The flaw affects versions 5.5.2, 6.0.1, and earlier releases. Manager accounts can craft XSS payloads that execute in the browsers of their own advertiser users due to improper neutralization of input [CWE-79]. Successful exploitation requires an authenticated manager account and user interaction from the targeted advertiser. The vulnerability carries a CVSS 3.1 score of 5.4 with a changed scope, reflecting cross-privilege-boundary impact between manager and advertiser accounts.
Critical Impact
Authenticated manager accounts can inject malicious scripts that execute in advertiser browsers, enabling session theft, credential capture, or unauthorized actions within the advertiser context.
Affected Products
- Revive Adserver 5.5.2
- Revive Adserver 6.0.0
- Revive Adserver 6.0.1 and earlier versions
Discovery Timeline
- 2025-11-20 - CVE-2025-55123 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-55123
Vulnerability Analysis
CVE-2025-55123 is a stored cross-site scripting flaw in Revive Adserver's manager-to-advertiser workflow. Revive Adserver uses a hierarchical account model where manager accounts create and administer advertiser accounts. The vulnerable code path fails to properly neutralize attacker-controlled input rendered in advertiser-facing interface elements. When an advertiser user views the affected page, the injected script executes in the advertiser's browser session. Because the payload crosses a privilege boundary from manager to advertiser, the CVSS scope is marked as changed. Reported publicly through HackerOne Report #3404968, the issue impacts confidentiality and integrity of the advertiser session.
Root Cause
The vulnerability stems from missing or insufficient output encoding when manager-supplied data is rendered in HTML contexts viewed by advertiser users. The application trusts input from higher-privileged manager accounts without applying context-aware escaping. Attacker-controlled strings persist in server-side storage and are later reflected into advertiser pages as executable script rather than inert text.
Attack Vector
Exploitation requires network access to the Revive Adserver instance, valid manager credentials, and interaction from an advertiser user. A malicious or compromised manager account submits a payload containing JavaScript into a field that is later displayed to their assigned advertisers. When the advertiser loads the affected page, the browser executes the script in the advertiser's origin context. Attackers can use this to steal session cookies, perform actions on behalf of the advertiser, or pivot to further account compromise.
No verified proof-of-concept code is publicly available. See the HackerOne Report #3404968 for additional technical details.
Detection Methods for CVE-2025-55123
Indicators of Compromise
- Manager account submissions containing HTML tags such as <script>, <img onerror=, or <svg onload= in fields intended for plaintext.
- Advertiser-facing pages returning stored content that includes inline event handlers or unexpected javascript: URIs.
- Outbound HTTP requests from advertiser browser sessions to domains not associated with the Revive Adserver deployment.
Detection Strategies
- Review Revive Adserver access logs for manager account activity that writes to advertiser-visible resources, correlating with subsequent advertiser page loads.
- Deploy a web application firewall (WAF) rule set that inspects request bodies for common XSS payloads submitted through the manager interface.
- Search the Revive Adserver database for stored values containing <, >, or JavaScript event handler substrings in text fields.
Monitoring Recommendations
- Enable Content Security Policy (CSP) reporting to capture script-src violations originating from advertiser sessions.
- Alert on anomalous manager-to-advertiser configuration changes, especially bulk edits or activity outside business hours.
- Track advertiser account authentication anomalies such as session reuse from unexpected IP addresses following manager updates.
How to Mitigate CVE-2025-55123
Immediate Actions Required
- Upgrade Revive Adserver to a version later than 5.5.2 and 6.0.1 that includes the vendor fix for CVE-2025-55123.
- Audit existing manager accounts and revoke credentials that are inactive, shared, or no longer required.
- Rotate advertiser session tokens and require re-authentication after applying the patch.
Patch Information
Apply the fixed release published by the Revive Adserver project. Consult the HackerOne Report #3404968 and the Revive Adserver project's release notes for the specific patched version and upgrade instructions.
Workarounds
- Restrict manager account creation to trusted personnel and enforce multi-factor authentication (MFA) on all manager logins.
- Deploy a strict Content Security Policy that disallows inline scripts and unsafe evaluation on advertiser-facing pages.
- Place the Revive Adserver management interface behind a WAF configured to block common XSS payloads until the patch is applied.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
