CVE-2026-23795 in Syncope
Summary
by MITRE • 02/03/2026
Improper Restriction of XML External Entity Reference vulnerability in Apache Syncope Console. An administrator with adequate entitlements to create or edit Keymaster parameters via Console can construct malicious XML text to launch an XXE attack, thereby causing sensitive data leakage occurs.
This issue affects Apache Syncope: from 3.0 through 3.0.15, from 4.0 through 4.0.3.
Users are recommended to upgrade to version 3.0.16 / 4.0.4, which fix this issue.
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Analysis
by VulDB Data Team • 02/04/2026
The vulnerability CVE-2026-23795 represents a critical improper restriction of XML external entity reference flaw within the Apache Syncope Console component. This weakness falls under the CWE-611 category of XML External Entity Processing, where the application fails to properly validate or sanitize XML input containing external entity references. The vulnerability specifically impacts the Keymaster parameter management functionality within the Syncope Console, which serves as the administrative interface for configuring and managing identity management policies and settings. Attackers can exploit this flaw through the administrative console's parameter editing capabilities, leveraging the XXE (XML External Entity) attack vector to access sensitive data from the underlying system.
The technical exploitation of this vulnerability requires an attacker to possess administrative privileges or sufficient entitlements to create or modify Keymaster parameters through the Console interface. This access level is crucial as it demonstrates the privilege escalation aspect of the vulnerability, where a relatively low-impact attack vector can be leveraged by authenticated users with appropriate permissions. The flaw allows attackers to construct malicious XML content that references external entities, potentially enabling them to read local files, perform server-side request forgery attacks, or access internal network resources. The vulnerability's impact is particularly severe in enterprise identity management environments where Syncope serves as a central authentication and authorization system.
The operational impact of this vulnerability extends beyond simple data leakage, potentially compromising the entire identity management infrastructure. Organizations using affected versions of Apache Syncope may experience unauthorized access to sensitive configuration data, user credentials stored in the system, or internal system information that could facilitate further attacks. The vulnerability affects multiple version ranges including Apache Syncope 3.0.0 through 3.0.15 and 4.0.0 through 4.0.3, indicating a widespread exposure across the product line. This affects organizations that rely on Syncope for identity management, particularly those with complex authentication systems where the Keymaster parameters control critical access controls and authorization mechanisms.
Organizations should immediately implement the recommended remediation by upgrading to Apache Syncope versions 3.0.16 or 4.0.4, which contain the necessary patches to address the XXE vulnerability. Security teams should also consider implementing additional monitoring and logging around Keymaster parameter modifications to detect potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for XML external entity processing and T1566 for server-side request forgery, making it a significant concern for organizations following the MITRE ATT&CK framework for threat analysis. Organizations should also review their access control policies to ensure that only authorized personnel have the ability to modify Keymaster parameters, reducing the attack surface for this particular vulnerability.