CVE-2026-58159 in Traffic Server
Summary
by MITRE • 07/29/2026
Apache Traffic Server can bypass IP access controls on UDS listeners and through ACL matching errors.
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
This vulnerability represents a critical access control bypass in Apache Traffic Server that allows unauthorized clients to circumvent network security restrictions imposed through Unix Domain Socket (UDS) listeners. The flaw stems from improper implementation of Access Control List (ACL) matching mechanisms specifically within the UDS listener component, enabling malicious actors to establish connections and potentially gain elevated privileges or access to restricted resources. The vulnerability affects multiple major versions including 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3, indicating a widespread issue across the software's lifecycle that has persisted for several release cycles.
The technical implementation error occurs within the ACL matching logic where UDS listeners fail to properly validate incoming connection requests against configured access restrictions. This allows attackers to exploit the inconsistency between how connections are authenticated and how access controls are enforced, essentially creating a pathway for unauthorized network access through Unix domain sockets that should have been protected by strict access controls. The flaw specifically manifests when clients attempt to connect via UDS endpoints while the system's ACL mechanisms do not properly enforce the intended restrictions, leading to potential privilege escalation or unauthorized data access scenarios.
Operational impact of this vulnerability extends beyond simple unauthorized access as it undermines fundamental network security assumptions within Apache Traffic Server deployments. Organizations relying on UDS listeners for internal service communication may experience complete compromise of their network segmentation strategies, particularly in environments where Unix domain sockets are used as a security boundary. The vulnerability could enable attackers to bypass firewalls, network isolation, and other protective measures that depend on proper ACL enforcement, potentially leading to full system compromise or data exfiltration through these previously protected communication channels.
Mitigation efforts should prioritize immediate upgrade to Apache Traffic Server versions 9.2.15 or 10.1.4 which contain the necessary patches addressing the ACL matching errors in UDS listener implementations. Organizations unable to immediately upgrade should consider implementing additional network-level controls such as firewall rules that restrict access to UDS endpoints, disabling unnecessary UDS listeners where possible, and monitoring for anomalous connection patterns that might indicate exploitation attempts. Security teams should also conduct thorough audits of their UDS configurations to identify all potentially affected listeners and ensure proper access control enforcement throughout their infrastructure. This vulnerability aligns with CWE-284 (Improper Access Control) and may be categorized under ATT&CK techniques related to privilege escalation and network infiltration through service exploitation, emphasizing the need for comprehensive security remediation across all affected deployments.
The vulnerability demonstrates how seemingly minor implementation flaws in access control systems can have cascading security implications, particularly when Unix domain sockets are involved in enterprise network architectures where these communication mechanisms often serve as trusted boundaries between application components. Given the widespread adoption of Apache Traffic Server in content delivery and proxy environments, this issue represents a significant concern for organizations managing large-scale web infrastructure deployments that rely on proper network segmentation for security posture maintenance.