A critical XML External Entity (XXE) vulnerability has been disclosed in the Syncope identity management console.
The flaw could allow administrators to expose sensitive user data and compromise session security inadvertently.
The vulnerability, tracked as CVE-2026-23795, affects multiple versions of the platform and requires immediate patching.
The improper restriction of XML External Entity references in Apache Syncope Console creates a pathway for XXE attacks when administrators create or edit Keymaster parameters.
An attacker with sufficient administrative entitlements can craft malicious XML payloads to trigger unintended data exposure.
| CVE ID | Vulnerability | CVSS Score | Affected Component | Affected Versions | Attack Vector | Impact |
|---|---|---|---|---|---|---|
| CVE-2026-23795 | XML External Entity (XXE) Injection | 6.5 | Apache Syncope Console | 3.0-3.0.15, 4.0-4.0.3 | Network | Data Exposure, Session Hijacking |
This attack vector bypasses normal security restrictions by exploiting the way the application processes XML input without proper validation and sanitization.
XXE vulnerabilities are among the most dangerous attack vectors in identity management systems because they operate at the application layer and can provide direct access to sensitive configuration data, user credentials, and authentication tokens.
In the context of Syncope’s role as a user identity and access management platform, the implications extend beyond individual sessions to potentially compromise the entire authentication infrastructure.
The vulnerability impacts Apache Syncope versions spanning two major release branches:
| Component | Affected Versions | Fixed Version |
|---|---|---|
| Syncope Client IdRepo Console (3.x) | 3.0 through 3.0.15 | 3.0.16 |
| Syncope Client IdRepo Console (4.x) | 4.0 through 4.0.3 | 4.0.4 |
Organizations running these versions should prioritize upgrading immediately.
The vulnerability requires administrator-level access to exploit, limiting direct external attack surface but creating significant insider threat risks.
Attack Methodology
The attack requires an administrator account with permissions to modify Keymaster parameters through the Syncope Console interface.
Once authenticated, the attacker constructs specially formatted XML containing external entity declarations pointing to sensitive system files or internal network resources.
When the application processes this malicious XML, it resolves the external entities and exposes their contents to the attacker.
This technique enables attackers to read arbitrary files from the server, access internal network resources, and potentially extract user session tokens or authentication credentials.
The issue is rated moderate because an attacker needs admin access first, but the possible impact is still large.
Apache recommends immediate upgrades to version 3.0.16 for users on the 3.x branch and version 4.0.4 for those on the 4.x branch.
Organizations unable to patch immediately should restrict administrative console access to trusted personnel and implement additional network monitoring to detect suspicious XML parsing activity.
Organizations managing identity infrastructure should review their deployment status and prioritize this patch in their security update schedule to prevent potential session hijacking and data exposure incidents.
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