CVE-2026-58162 in Traffic Server
Summary
by MITRE • 07/29/2026
The Apache Traffic Server certifier plugin generates certificates based on attacker-controlled client SNI.
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 Apache Traffic Server certifier plugin vulnerability represents a critical security flaw that allows remote attackers to manipulate certificate generation processes through controlled client Server Name Indication (SNI) parameters. This issue exists within the certificate authority implementation of the traffic server software, where the system fails to properly validate or sanitize SNI values provided by clients during TLS handshakes. The vulnerability specifically impacts multiple versions of Apache Traffic Server across its major release lines, creating a widespread exposure that affects organizations relying on this caching and proxy infrastructure.
The technical root cause stems from insufficient input validation within the certificate generation workflow where the certifier plugin directly uses attacker-controlled SNI values to construct certificate subjects without proper sanitization or authorization checks. This creates a path for malicious actors to influence certificate attributes including subject names, organizational units, and other identifying information that would normally be generated through legitimate server configuration processes. The flaw operates at the TLS protocol layer where SNI data is transmitted during initial handshake negotiations, making it accessible to attackers who can craft specific SNI values to manipulate certificate content. This vulnerability falls under CWE-20, Input Validation, and specifically relates to improper validation of input parameters used in security-sensitive operations.
The operational impact of this vulnerability extends beyond simple certificate manipulation to potentially enable advanced attack vectors including man-in-the-middle scenarios, credential harvesting, and impersonation attacks against legitimate services. Attackers could generate certificates with misleading subject names that appear to belong to trusted entities, facilitating trust exploitation and bypassing typical certificate validation checks. Organizations using Apache Traffic Server as a proxy or caching layer may experience compromised security postures where legitimate client traffic becomes vulnerable to interception or manipulation. The vulnerability creates opportunities for attackers to establish persistent access points through forged certificates that could be accepted by clients due to the trusted nature of the server infrastructure.
Mitigation strategies should prioritize immediate upgrade to patched versions 9.2.15 or 10.1.4, which implement proper SNI validation and certificate generation controls. Organizations lacking immediate upgrade capabilities should consider implementing network-level restrictions to limit exposure, disabling unnecessary certificate generation features, and monitoring for anomalous certificate issuance patterns. The fix addresses the core validation issue by ensuring that SNI values are properly sanitized before being used in certificate subject construction, preventing attackers from injecting malicious content into generated certificates. Security teams should also conduct comprehensive audits of their certificate management practices and implement additional monitoring controls to detect unauthorized certificate generation activities.
This vulnerability demonstrates the critical importance of input validation in security-sensitive components and aligns with ATT&CK technique T1552.001 for credentials in files, as compromised certificates can be used to gain unauthorized access to protected resources. The issue highlights common patterns found in web infrastructure where protocol-level parameters are not properly validated before being used in security-critical operations, making it a significant concern for organizations relying on proxy and caching services for their network security posture.