CVE-2024-52317: Apache Tomcat Request Mix-Up Vulnerability

CVE-2024-52317 Overview

CVE-2024-52317 is an incorrect object re-cycling and re-use vulnerability in Apache Tomcat that affects HTTP/2 request processing. The vulnerability stems from improper recycling of request and response objects, which can lead to request and/or response mix-up between different users on the same server. This represents a serious security concern for multi-tenant environments where user data isolation is critical.

Critical Impact

HTTP/2 request/response handling errors can cause sensitive data from one user's session to be inadvertently exposed to another user, potentially leaking authentication tokens, session data, or personal information.

Affected Products

• Apache Tomcat 11.0.0-M23 through 11.0.0-M26
• Apache Tomcat 10.1.27 through 10.1.30
• Apache Tomcat 9.0.92 through 9.0.95

Discovery Timeline

• 2024-11-18 - CVE-2024-52317 published to NVD
• 2025-05-15 - Last updated in NVD database

Technical Details for CVE-2024-52317

Vulnerability Analysis

This vulnerability is classified under CWE-326 and involves incorrect recycling of HTTP/2 request and response objects within Apache Tomcat's HTTP/2 implementation. When multiple concurrent HTTP/2 requests are processed, the server may improperly recycle and reuse request/response objects before they are fully processed or cleared. This can result in data from one user's request being inadvertently associated with another user's response, creating a cross-user information disclosure scenario.

The vulnerability specifically affects environments using HTTP/2 protocol connections, where connection multiplexing allows multiple requests to share a single TCP connection. The object pooling mechanism intended to improve performance by reusing request/response objects fails to properly isolate data between different streams.

Root Cause

The root cause of CVE-2024-52317 lies in the incorrect implementation of object lifecycle management within Tomcat's HTTP/2 stream handling code. Request and response objects are being returned to the object pool for reuse before their data has been completely cleared or while still referenced by other processing threads. This race condition allows residual data from previous requests to leak into subsequent requests handled by different users.

Attack Vector

This vulnerability is exploitable over the network without requiring authentication. An attacker does not need to actively exploit this vulnerability—the data leakage occurs naturally as a side effect of normal HTTP/2 request processing under specific timing conditions. The attack scenario involves:

1. Multiple users connecting to the same Apache Tomcat server using HTTP/2
2. Concurrent requests being processed through the vulnerable object recycling mechanism
3. Timing conditions causing request/response data to be mixed between different user sessions
4. Sensitive information such as session cookies, authentication tokens, or response bodies being exposed to unintended recipients

The vulnerability does not require any special privileges or user interaction, making it a passive information disclosure risk that can occur during normal server operation.

Detection Methods for CVE-2024-52317

Indicators of Compromise

• Users reporting receiving data or responses that belong to other users
• Unexpected session behavior where users see content from other accounts
• Log entries showing mismatched session IDs with request content
• HTTP/2 stream processing errors in Tomcat access logs

Detection Strategies

• Monitor application logs for user reports of seeing other users' data
• Implement application-level logging that tracks session IDs against response content
• Use network monitoring to detect anomalous HTTP/2 stream behavior
• Review Tomcat version inventory to identify affected installations

Monitoring Recommendations

• Enable detailed HTTP/2 connection logging in Apache Tomcat configurations
• Implement session integrity monitoring at the application layer
• Set up alerts for unusual patterns in HTTP/2 stream multiplexing
• Deploy application performance monitoring (APM) tools to track request/response correlation

How to Mitigate CVE-2024-52317

Immediate Actions Required

• Upgrade Apache Tomcat to version 11.0.0, 10.1.31, or 9.0.96 immediately
• Review the Apache Mailing List Thread for official vendor guidance
• Audit systems to identify all Apache Tomcat installations running vulnerable versions
• Consider temporarily disabling HTTP/2 support if immediate patching is not possible

Patch Information

Apache has released patched versions that address this vulnerability. Users are recommended to upgrade to:

• Apache Tomcat 11.0.0 (for 11.x milestone users)
• Apache Tomcat 10.1.31 (for 10.1.x users)
• Apache Tomcat 9.0.96 (for 9.0.x users)

Consult the Apache Mailing List Thread for detailed upgrade instructions and release notes. Additional information is available through the NetApp Security Advisory and the OpenWall OSS Security List.

Workarounds

• Disable HTTP/2 protocol support and revert to HTTP/1.1 as a temporary measure
• Implement a reverse proxy in front of Tomcat that handles HTTP/2 termination
• Restrict access to affected Tomcat instances until patching can be completed
• Apply network segmentation to limit exposure of vulnerable servers

# Disable HTTP/2 in Tomcat server.xml configuration
# Locate the Connector element and ensure HTTP/2 upgrade protocol is removed
# Example: Remove or comment out the UpgradeProtocol element for h2c

# In server.xml, modify the Connector:
# <Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol"
#            maxThreads="150" SSLEnabled="true">
#     <!-- Remove or comment out the following line -->
#     <!-- <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" /> -->
# </Connector>