Executive Summary
A critical vulnerability (CVE-2026-58150) has been identified in Apache Traffic Server, a popular open-source caching proxy server. This vulnerability allows for downgrade request smuggling and has a CVSS score of 10, indicating the highest severity level. The affected versions include Apache Traffic Server 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.
Technical Analysis
The vulnerability is caused by Apache Traffic Server not rejecting Transfer-Encoding in HTTP/2 requests, which allows for downgrade request smuggling. This issue falls under the CWE-444 category. The attack vector is network-based, with low attack complexity and no privileges required.
How It Gets Exploited
An attacker can exploit this vulnerability by sending a crafted HTTP/2 request with a Transfer-Encoding header to an affected Apache Traffic Server instance. The server fails to properly handle the request, allowing the attacker to smuggle requests and potentially bypass security controls. This can lead to unauthorized access, data tampering, or other malicious activities.
Impact Assessment
The impact of this vulnerability is significant, with a CVSS score of 10 indicating critical severity. Successful exploitation can lead to high confidentiality and integrity impacts, with the potential for request smuggling and unauthorized access to sensitive data. The affected versions include Apache Traffic Server 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3.
Recommended Actions
To mitigate this vulnerability, users are strongly recommended to upgrade to Apache Traffic Server version 9.2.15 or 10.1.4, which fix the issue. Additionally, users should monitor their Apache Traffic Server instances for suspicious activity and implement network segmentation and access controls to limit the attack surface.
Sources
- National Vulnerability Database (NVD)
- Apache Software Foundation