CVE-2025-48795: Apache CXF Denial of Service Vulnerability

CVE-2025-48795 Overview

Apache CXF, a widely-used open-source services framework, contains a vulnerability in how it handles large stream-based messages stored as temporary files. A bug was introduced which causes the entire temporary file to be read into memory and then logged, creating two distinct security issues: potential denial of service through memory exhaustion and information disclosure of sensitive data through unencrypted logging.

Critical Impact

Attackers can exploit this vulnerability to cause denial of service through out-of-memory exceptions, and sensitive credentials configured to be encrypted in temporary files may be written to logs in plaintext.

Affected Products

• Apache CXF version 3.5.10
• Apache CXF version 3.6.5
• Apache CXF version 4.0.6
• Apache CXF version 4.1.0

Discovery Timeline

• 2025-07-15 - CVE-2025-48795 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-48795

Vulnerability Analysis

This vulnerability (CWE-400: Uncontrolled Resource Consumption) stems from improper handling of temporary files in Apache CXF's message processing pipeline. When CXF processes large stream-based messages, it stores them as temporary files on the local filesystem to manage memory efficiently. However, a bug in the implementation causes the entire contents of these temporary files to be loaded into memory during logging operations.

The dual impact of this vulnerability makes it particularly concerning for enterprise environments. First, the memory consumption issue allows attackers to craft specially sized messages that, when processed and logged, trigger Java heap exhaustion leading to application crashes. Second, organizations that have configured CXF to encrypt temporary files—specifically to protect sensitive credentials from being stored in plaintext on disk—find their security controls bypassed when the encrypted content is written to logs without encryption.

Root Cause

The root cause lies in the logging subsystem's interaction with the temporary file storage mechanism. When logging is enabled for message content, the code path reads the entire temporary file into memory rather than streaming it or logging only metadata. This violates the original design intent of using temporary files to avoid memory pressure from large messages.

Additionally, the logging function bypasses the encryption layer that may be configured for temporary file storage, directly reading and outputting the decrypted content to log files.

Attack Vector

The attack vector is network-based, requiring an attacker to send specially crafted large messages to an Apache CXF service endpoint. The attack complexity is considered high as it depends on specific logging configurations being enabled and the target environment's memory constraints.

An attacker would craft oversized stream-based messages and send them to the vulnerable CXF endpoint. When the service processes these messages and the logging subsystem attempts to log them, the entire message content is loaded into the JVM heap. By sending multiple large messages or a single extremely large message, an attacker can exhaust available memory and cause the application to crash with an OutOfMemoryError.

For information disclosure scenarios, the attacker would need knowledge that sensitive data is being transmitted through the CXF service and that temporary file encryption is configured. The decrypted content appearing in logs could then be accessed if log files are improperly secured or accessible to unauthorized parties.

Detection Methods for CVE-2025-48795

Indicators of Compromise

• Unusual spikes in JVM heap memory usage during message processing
• OutOfMemoryError exceptions in application logs correlated with large incoming requests
• Unexpectedly large log files containing base64-encoded or plaintext message content
• Application crashes or service unavailability following receipt of large SOAP/REST messages

Detection Strategies

• Monitor JVM heap utilization metrics and alert on rapid memory consumption patterns
• Implement log analysis rules to detect unusually large log entries that may contain full message payloads
• Deploy application performance monitoring (APM) to track message processing latency and memory allocation
• Audit log files for presence of sensitive credential data that should be encrypted

Monitoring Recommendations

• Configure memory threshold alerts for Apache CXF service instances
• Implement network-level monitoring for abnormally large incoming message payloads
• Review log rotation policies to identify unexpected log size growth
• Enable SentinelOne Singularity for real-time detection of resource exhaustion attacks

How to Mitigate CVE-2025-48795

Immediate Actions Required

• Upgrade to Apache CXF version 3.5.11, 3.6.6, 4.0.7, or 4.1.1 immediately
• Review current logging configurations and disable verbose message logging until patched
• Implement JVM memory limits and restart policies to contain DoS impact
• Audit existing log files for inadvertent disclosure of sensitive credentials

Patch Information

Apache has released fixed versions that address this vulnerability. Users should upgrade to the following versions based on their current deployment:

For additional details, consult the Apache Mailing List Discussion and the Openwall OSS-Security Update.

Workarounds

• Disable message content logging by setting appropriate CXF logging properties to prevent full message capture
• Implement request size limits at the web server or load balancer level to reject oversized messages
• Increase JVM heap size temporarily while preparing for upgrade (note: this reduces DoS impact but does not address information disclosure)
• Ensure log files are stored with restrictive permissions and encrypted at rest to minimize credential exposure risk

# Example: Configure CXF to disable message logging
# Add to cxf.xml or Spring configuration
# Set logging feature to not log message content
# <cxf:bus>
#   <cxf:features>
#     <bean class="org.apache.cxf.ext.logging.LoggingFeature">
#       <property name="logBinary" value="false"/>
#       <property name="logMultipart" value="false"/>
#       <property name="limit" value="1024"/>
#     </bean>
#   </cxf:features>
# </cxf:bus>