CVE-2025-58136: Apache Traffic Server DoS Vulnerability

CVE-2025-58136 Overview

A vulnerability in Apache Traffic Server's POST request handling mechanism can cause the server to crash under certain conditions. This denial of service flaw affects the stability of proxy infrastructure, potentially disrupting service availability for organizations relying on Apache Traffic Server for their web traffic management.

The vulnerability is classified under CWE-670 (Always-Incorrect Control Flow Implementation), indicating a fundamental issue in how the server processes certain POST requests, leading to an unhandled exception or crash condition.

Critical Impact

Unauthenticated remote attackers can crash Apache Traffic Server instances via specially crafted POST requests, causing denial of service to all proxied applications and services.

Affected Products

• Apache Traffic Server versions 10.0.0 through 10.1.1
• Apache Traffic Server versions 9.0.0 through 9.2.12

Discovery Timeline

• 2026-04-02 - CVE-2025-58136 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2025-58136

Vulnerability Analysis

This vulnerability stems from improper control flow implementation in Apache Traffic Server's POST request handling code. When specific conditions are met during POST request processing, the server fails to properly handle the request state, resulting in a crash. The flaw allows unauthenticated attackers to remotely trigger the crash condition over the network without requiring any user interaction.

The vulnerability specifically involves the request buffering mechanism within the Traffic Server. The crash occurs when the server encounters a particular combination of request parameters or conditions that were not properly accounted for in the control flow logic. This represents a reliability issue that can be exploited to disrupt service availability.

Root Cause

The root cause is tied to CWE-670: Always-Incorrect Control Flow Implementation. The POST request handling logic contains a code path that leads to an unrecoverable state under certain input conditions. The request buffer handling component fails to properly validate or handle edge cases, causing the server process to terminate unexpectedly. The configuration option proxy.config.http.request_buffer_enabled is directly related to this vulnerability, as disabling it (setting to 0) prevents the vulnerable code path from being executed.

Attack Vector

The attack can be conducted remotely over the network by sending crafted POST requests to the Apache Traffic Server. No authentication or special privileges are required to exploit this vulnerability. The attack does not require user interaction and can be performed against any exposed Traffic Server instance running affected versions.

The exploitation mechanism involves sending POST requests that trigger the specific condition causing the crash. Since the default value for proxy.config.http.request_buffer_enabled is 0 (disabled), installations using non-default configurations with this option enabled to 1 are at risk. Successful exploitation results in service disruption, requiring a server restart to restore functionality.

Detection Methods for CVE-2025-58136

Indicators of Compromise

• Unexpected Apache Traffic Server process terminations or crashes
• Abnormal patterns of POST requests in access logs preceding crashes
• Core dumps or crash logs indicating failures in request handling routines
• Repeated service restarts detected in system monitoring

Detection Strategies

• Monitor Apache Traffic Server process health and implement alerting on unexpected terminations
• Analyze incoming POST request patterns for anomalies that could indicate exploitation attempts
• Review Traffic Server error logs for crash-related entries
• Implement network-level monitoring to detect potential denial of service attack patterns

Monitoring Recommendations

• Enable comprehensive logging for Apache Traffic Server request handling
• Configure process monitoring to detect and alert on Traffic Server crashes
• Implement automated service recovery with crash notification systems
• Monitor system resources and Traffic Server performance metrics for anomalies

How to Mitigate CVE-2025-58136

Immediate Actions Required

• Verify your Apache Traffic Server version and determine if you are running an affected version
• Apply the recommended workaround by ensuring proxy.config.http.request_buffer_enabled is set to 0
• Plan and schedule an upgrade to patched versions (10.1.2 or 9.2.13)
• Monitor Traffic Server instances for stability issues while preparing upgrades

Patch Information

Apache has released security patches addressing this vulnerability. Users running affected versions should upgrade to the following fixed releases:

• Version 10.x users: Upgrade to version 10.1.2 or later
• Version 9.x users: Upgrade to version 9.2.13 or later

For detailed information about the security fix, refer to the Apache Security Discussion Thread.

Workarounds

• Set proxy.config.http.request_buffer_enabled to 0 in your Traffic Server configuration (this is the default value)
• Implement rate limiting on POST requests at the network perimeter as a defense-in-depth measure
• Consider deploying a Web Application Firewall (WAF) to filter potentially malicious requests
• Ensure monitoring and automatic restart capabilities are in place to minimize downtime from potential crashes

# Configuration workaround for Apache Traffic Server
# Edit records.config to disable request buffering

# Set proxy.config.http.request_buffer_enabled to 0 (default)
CONFIG proxy.config.http.request_buffer_enabled INT 0

# Restart Traffic Server to apply changes
traffic_ctl config reload