CVE-2026-19633 in PostgreSQL Anonymizer
Summary
by MITRE • 09/06/2026
PostgreSQL Anonymizer contains a vulnerability that allows unprivileged masked users to execute arbitrary code by abusing operators, domain casts, or view subqueries that carry untrusted expressions. When these objects are evaluated in the context of the extension’s masking mechanisms, the malicious code can run with elevated privileges. The issue is fixed in PostgreSQL Anonymizer 3.1.4 and later versions
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Analysis
by VulDB Data Team • 09/06/2026
The vulnerability identified within the PostgreSQL Anonymizer extension represents a critical privilege escalation flaw that stems from improper validation of user-supplied input during the evaluation of database objects. Specifically, unprivileged masked users are able to execute arbitrary code by exploiting operators, domain casts, or view subqueries that contain untrusted expressions. In normal operation, these constructs should be treated as data or simple structural elements within the masking logic. However, due to a failure in sanitizing or restricting the execution context of these expressions, the database engine evaluates them with elevated privileges associated with the extension's internal mechanisms rather than the limited permissions of the calling user. This architectural oversight allows an attacker who has only basic access rights to bypass security controls and achieve code execution at a higher privilege level, effectively compromising the integrity and confidentiality of the entire PostgreSQL instance.
From a technical perspective, this flaw aligns closely with CWE-78 Improper Neutralization of Special Elements used in an OS Command or SQL Injection, as well as CWE-200 Exposure of Sensitive Information to an Unauthorized Actor if sensitive data is accessed during exploitation. The attack vector leverages the dynamic nature of PostgreSQL's type system and expression evaluation engine. By crafting specific domain casts or embedding malicious logic within view subqueries, attackers can trick the anonymizer into executing code in a context where it has access to internal functions that are normally restricted. This abuse of operators allows for arbitrary command execution on the underlying operating system if the database server is configured with appropriate permissions, leading to full compromise of the host environment. The vulnerability highlights the risks associated with allowing complex expression evaluation within security-critical extensions without rigorous input validation and context isolation.
The operational impact of this vulnerability is severe, as it undermines the fundamental purpose of using a data anonymization tool in production environments. Organizations rely on PostgreSQL Anonymizer to protect sensitive personal or proprietary information while still allowing developers and analysts access to realistic but masked datasets for testing and development purposes. If an unprivileged user can escalate their privileges through this flaw, they not only gain unauthorized code execution capabilities but also potentially bypass the masking rules entirely. This could result in the exposure of raw, unmasked data that should have been obscured, violating regulatory compliance requirements such as GDPR or HIPAA. Furthermore, arbitrary code execution on the database server poses a significant risk to system stability and security, enabling attackers to install malware, exfiltrate additional data, or use the compromised server as a pivot point for further network attacks.
Mitigation strategies primarily involve upgrading to PostgreSQL Anonymizer version 3.1.4 or later, where this issue has been addressed by developers through stricter validation of expressions passed within operators, domain casts, and view subqueries. Until an upgrade is feasible, administrators should enforce strict least-privilege principles on the database accounts that interact with the anonymization extension. It is advisable to restrict which users can create or modify views, domains, or custom operators that might be exploited in this manner. Additionally, monitoring for unusual query patterns involving complex nested expressions or unexpected privilege changes can help detect attempted exploitation activities. Security teams should also review their ATT&CK mapping for this vulnerability, noting its classification under T1059 Command and Scripting Interpreter if code execution is achieved, and ensure that endpoint detection and response tools are tuned to identify suspicious processes spawned by the PostgreSQL service account.