CVE-2026-108564 in Adserver
Summary
by MITRE • 11/11/2026
A reflected cross-site scripting vulnerability in the invocation-tag generation interface of Revive Adserver 6.0.8 and earlier allows an unauthenticated attacker to execute JavaScript in an authenticated user's browser by persuading them to visit a crafted URL. When Direct Selection is enabled, an attacker-controlled banner identifier can be included in HTML form fields without appropriate encoding. Direct Selection is disabled by default. The issue is fixed in Revive Adserver 6.0.9 by HTML-encoding banner identifier values in the invocation-option form fields.
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Analysis
by VulDB Data Team • 11/11/2026
The vulnerability identified as a reflected cross-site scripting flaw within Revive Adserver versions 6.0.8 and earlier stems from insufficient input validation and output encoding mechanisms in the invocation-tag generation interface. This specific component is responsible for creating ad tags that are embedded into third-party websites to display advertisements. The core technical failure occurs when Direct Selection, a feature allowing users to manually specify banner identifiers rather than relying on automated selection logic, is enabled by an administrator. Although this feature is disabled by default in standard configurations, its activation exposes the application to injection attacks if proper sanitization procedures are not enforced during data processing.
When an attacker crafts a malicious URL containing specially constructed parameters that include HTML special characters within the banner identifier field, these inputs are reflected back into the HTTP response without adequate encoding. The server-side logic fails to escape critical characters such as angle brackets and quotation marks before rendering them in the generated HTML form fields or invocation tags. Consequently, when an authenticated user with administrative privileges visits this crafted URL while logged into the Revive Adserver interface, their browser interprets the injected script code as part of the page content rather than plain text. This allows for the execution of arbitrary JavaScript within the context of the application's domain and security level.
The operational impact of this vulnerability is significant due to the authentication requirement associated with accessing the administrative functions that generate these tags. An unauthenticated attacker can exploit this by persuading a privileged user, such as an ad operations manager or system administrator, to click on a link hosted on a malicious external site. Once executed, the injected script operates under the session cookies and permissions of the authenticated user. This enables the attacker to perform actions on behalf of the victim, including modifying advertising campaigns, stealing sensitive configuration data, exfiltrating session tokens, or potentially pivoting to further attacks against internal network resources if the ad server is integrated with other systems. The attack vector relies heavily on social engineering tactics to trick high-privilege users into initiating the request.
From a classification perspective, this vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. Specifically, it represents a reflected XSS scenario where user-controllable data is included in web pages sent to other users without validation or escaping. In terms of the MITRE ATT&CK framework, this exploit maps to techniques involving Client-side Injection and potentially Credential Access if session tokens are harvested. The lack of output encoding constitutes a fundamental violation of secure coding practices that mandate treating all user input as untrusted until it has been validated and properly encoded for its specific context.
Mitigation strategies focus primarily on upgrading the software infrastructure immediately. Administrators running Revive Adserver 6.0.8 or earlier should upgrade to version 6.0.9, which implements a fix by ensuring that banner identifier values in invocation-option form fields are HTML-encoded before being rendered. This encoding neutralizes any script tags embedded within the input data, preventing them from executing as active code. For environments where upgrading is not immediately feasible, administrators can mitigate risk by disabling Direct Selection if it is currently enabled and restricting access to the invocation-tag generation interface through strict network segmentation or additional authentication layers such as multi-factor authentication for administrative accounts. Regular security audits of web application input handling processes are also recommended to prevent similar encoding flaws in other modules.