CVE-2025-53689: Apache Jackrabbit XXE Vulnerability

CVE-2025-53689 Overview

CVE-2025-53689 is a blind XML External Entity (XXE) vulnerability affecting the jackrabbit-spi-commons and jackrabbit-core modules in Apache Jackrabbit versions prior to 2.23.2. The flaw stems from an unsecured document builder used to load privileges, allowing authenticated attackers to inject malicious XML entities. Successful exploitation enables out-of-band data exfiltration, server-side request forgery, and disruption of the content repository. The vulnerability is tracked under CWE-611 (Improper Restriction of XML External Entity Reference).

Critical Impact

Authenticated attackers can leverage blind XXE injection to read internal files, perform SSRF against backend services, and compromise the confidentiality, integrity, and availability of Apache Jackrabbit content repositories.

Affected Products

• Apache Jackrabbit versions up to and including 2.20.16 (Java 8 branch)
• Apache Jackrabbit version 2.22.0 (Java 11 branch)
• Apache Jackrabbit versions 2.23.0-beta and 2.23.1-beta

Discovery Timeline

• 2025-07-14 - CVE-2025-53689 published to the National Vulnerability Database
• 2025-07-14 - Vulnerability disclosed via Openwall OSS Security Discussion
• 2025-07-14 - Apache Software Foundation announcement via Apache Mailing List Thread
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-53689

Vulnerability Analysis

The vulnerability resides in the XML parsing logic used by Apache Jackrabbit when loading privilege definitions. The affected modules instantiate a DocumentBuilder without disabling external entity processing or DTD resolution. When a crafted XML payload is processed, the parser dereferences external entities defined in a Document Type Definition (DTD).

Because the parser does not return parsed content directly to the caller, the issue manifests as a blind XXE condition. Attackers must rely on out-of-band channels — typically HTTP or DNS callbacks to attacker-controlled infrastructure — to extract data. This pattern allows exfiltration of local files readable by the Jackrabbit process and probing of internal network services.

Root Cause

The root cause is the use of an unsecured javax.xml.parsers.DocumentBuilderFactory instance during privilege loading. The factory is not configured with FEATURE_SECURE_PROCESSING, nor are the disallow-doctype-decl, external-general-entities, and external-parameter-entities features disabled. This default behavior permits resolution of external entities referenced in DOCTYPE declarations.

Attack Vector

An authenticated user with privileges to submit or influence XML content processed by the privilege loader can supply a payload containing an external DTD reference. The DTD instructs the parser to fetch a parameter entity from an attacker-controlled server, then transmit local file contents through a secondary URL request. Network-based exploitation is feasible because Apache Jackrabbit is commonly deployed behind web-facing applications such as Adobe Experience Manager and other content repositories. No code examples are published in the available references — see the Apache Mailing List Thread for vendor details.

Detection Methods for CVE-2025-53689

Indicators of Compromise

• Outbound DNS or HTTP requests from the Jackrabbit JVM process to unfamiliar external hosts, particularly during privilege-loading operations
• XML payloads in application logs containing <!DOCTYPE, <!ENTITY, or SYSTEM references targeting file://, http://, or ftp:// URIs
• Unexpected reads of sensitive files such as /etc/passwd, application configuration files, or credential stores by the Jackrabbit process
• Java stack traces referencing DocumentBuilder, SAXParser, or entity resolution errors during privilege initialization

Detection Strategies

• Inspect HTTP request bodies and uploaded XML documents for DOCTYPE declarations and parameter entity definitions
• Correlate Jackrabbit process activity with outbound network flows to detect callback channels typical of blind XXE
• Audit privilege-load operations and compare against a baseline of expected XML inputs
• Deploy egress filtering and DNS monitoring to surface anomalous resolution attempts originating from application servers

Monitoring Recommendations

• Forward Apache Jackrabbit application logs, JVM logs, and web server access logs to a centralized logging platform for retention and correlation
• Monitor for new outbound connections from servers hosting Jackrabbit that do not match documented integrations
• Alert on file-access patterns showing the Jackrabbit JVM reading files outside the repository data directory

How to Mitigate CVE-2025-53689

Immediate Actions Required

• Upgrade Apache Jackrabbit to version 2.20.17 for Java 8 deployments, 2.22.1 for Java 11 deployments, or 2.23.2 for beta tracks
• Inventory all applications embedding jackrabbit-spi-commons or jackrabbit-core, including downstream products such as content management platforms
• Restrict access to authenticated endpoints that accept XML input until patches are applied
• Enforce strict egress filtering from servers running Jackrabbit to block out-of-band XXE callback channels

Patch Information

The Apache Software Foundation released fixed versions 2.20.17, 2.22.1, and 2.23.2. Earlier versions up to 2.20.16 are no longer supported and must be upgraded to a supported branch. Refer to the Apache Mailing List Thread for the official advisory and release notes.

Workarounds

• Place a reverse proxy or web application firewall in front of Jackrabbit endpoints to strip DOCTYPE declarations from inbound XML payloads
• Remove network egress permissions from the Jackrabbit application server to prevent blind XXE callbacks until patches are deployed
• Limit privileged access so that only trusted administrators can submit XML used by the privilege loader

# Example egress restriction using iptables to block outbound traffic
# from the Jackrabbit application server (replace eth0 and ranges as needed)
iptables -A OUTPUT -o eth0 -m owner --uid-owner jackrabbit -d 10.0.0.0/8 -j ACCEPT
iptables -A OUTPUT -o eth0 -m owner --uid-owner jackrabbit -j DROP