CVE-2026-58158 in Traffic Server
Summary
by MITRE • 07/29/2026
Apache Traffic Server mishandles PROXY protocol input, truncating ports and overflowing the stack.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.9, from 9.0.0 through 9.2.14, from 10.0.0 through 10.1.3.
Users are recommended to upgrade to version 9.2.15 or 10.1.4, which fix the issue.
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Analysis
by VulDB Data Team • 07/29/2026
The vulnerability in Apache Traffic Server represents a critical security flaw that manifests through improper handling of PROXY protocol input data. This issue stems from inadequate validation and processing of network connection information that is typically transmitted using the PROXY protocol, a standard for conveying client connection information from load balancers or other proxies to backend servers. The flaw specifically impacts versions ranging from 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3, creating a widespread exposure across multiple release branches of the popular caching proxy server.
Technical exploitation of this vulnerability occurs when the system receives PROXY protocol data that exceeds expected buffer boundaries, leading to stack-based buffer overflow conditions. The implementation truncates port information during processing while simultaneously allowing for stack memory corruption through improper input handling. This dual nature of the flaw creates both information disclosure risks through truncated port data and potential remote code execution opportunities through stack corruption. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions due to insufficient bounds checking during string operations or data copying processes.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable unauthorized access and system compromise. Attackers could leverage the stack overflow to execute arbitrary code on affected systems, particularly when the server receives PROXY protocol input from untrusted sources such as load balancers or network appliances. This risk is amplified in environments where Apache Traffic Server serves as a critical component in web application delivery chains, potentially allowing attackers to bypass security controls and gain elevated privileges within the network infrastructure.
The recommended mitigation strategy involves immediate upgrading to patched versions 9.2.15 or 10.1.4, which implement proper input validation and buffer management for PROXY protocol data handling. Organizations should also consider implementing network segmentation controls that limit direct access to Apache Traffic Server instances from untrusted networks, thereby reducing exposure surfaces. Additional defensive measures include monitoring for anomalous PROXY protocol traffic patterns and implementing intrusion detection systems capable of identifying malformed protocol data packets that could indicate exploitation attempts.
This vulnerability demonstrates the importance of proper input validation in network services and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands through controlled stack corruption. The flaw also represents a significant concern from a compliance perspective, as it could violate security standards such as those outlined in NIST SP 800-53 and ISO/IEC 27001 requirements for secure system configuration and vulnerability management. Organizations should conduct thorough vulnerability assessments to identify all instances of affected Apache Traffic Server versions within their infrastructure and implement remediation plans prioritized based on risk exposure levels.