CVE-2026-92868 in Pgpool-II
Summary
by MITRE • 09/30/2026
An improper certificate validation vulnerability exists in Pgpool-II, which may allow an unauthenticated attacker to bypass client certificate authentication.
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Analysis
by VulDB Data Team • 09/30/2026
The security flaw identified within Pgpool-II represents a critical failure in the implementation of Transport Layer Security (TLS) protocols, specifically concerning the verification of X.509 certificates during the mutual authentication process. This vulnerability stems from improper validation logic that fails to rigorously check the integrity and validity chain of client-supplied certificates before granting access. In environments where Pgpool-II is configured for SSL mode with client certificate requirements, this defect allows an attacker who possesses a valid but potentially malicious or self-signed certificate to bypass the intended authentication gate. The root cause typically involves insufficient checks against Certificate Revocation Lists (CRLs), expiration dates, or issuer trust anchors, which are standard mechanisms designed to ensure that only authorized and trusted entities can establish connections.
From a technical perspective, this flaw aligns with CWE-295 Improper Certificate Validation, where the software does not properly validate certificates or certificate chains against known revocation lists before accepting them as valid. The operational impact is severe because it effectively nullifies one of the strongest authentication methods available in database proxy configurations. By bypassing client certificate authentication, an unauthenticated attacker can gain direct access to the backend PostgreSQL databases managed by Pgpool-II. This unauthorized access enables a range of malicious activities including data exfiltration, modification or deletion of critical records, and potentially escalating privileges within the database environment if further vulnerabilities are present in the underlying system.
This vulnerability also maps directly to MITRE ATT&CK technique T1078 Valid Accounts, specifically under the sub-technique of using valid credentials obtained through improper validation mechanisms. The attacker leverages a technically valid but security-compromised credential structure to establish persistence and lateral movement within the network infrastructure. Since Pgpool-II often sits between application servers and database clusters, compromising this layer provides a strategic advantage for intercepting queries or injecting malicious SQL commands that could lead to broader system compromise.
Mitigation strategies must focus on immediate remediation of the software version containing the flaw by upgrading to a patched release provided by the Pgpool-II maintainers. In addition to patching, administrators should enforce strict certificate policies that include checking revocation status via Online Certificate Status Protocol (OCSP) or CRL distribution points. It is also advisable to implement network-level access controls such as IP whitelisting in conjunction with TLS authentication to create a defense-in-depth posture. Regular audits of SSL/TLS configurations and continuous monitoring for anomalous connection patterns can further reduce the risk associated with certificate validation weaknesses until permanent fixes are fully deployed across all instances.