CVE-2026-2004: PostgreSQL intarray Extension RCE Flaw

CVE-2026-2004 Overview

A critical input validation vulnerability exists in the PostgreSQL intarray extension's selectivity estimator function. This flaw allows an authenticated object creator to execute arbitrary code with the privileges of the operating system user running the PostgreSQL database server. The vulnerability stems from improper validation of input types (CWE-1287), enabling attackers who can create database objects to escalate their access and potentially compromise the underlying system.

Critical Impact

An authenticated database user with object creation privileges can execute arbitrary code as the database server's OS user, potentially leading to full system compromise.

Affected Products

• PostgreSQL versions before 18.2
• PostgreSQL versions before 17.8
• PostgreSQL versions before 16.12
• PostgreSQL versions before 15.16
• PostgreSQL versions before 14.21

Discovery Timeline

• February 12, 2026 - CVE-2026-2004 published to NVD
• February 12, 2026 - Last updated in NVD database

Technical Details for CVE-2026-2004

Vulnerability Analysis

This vulnerability resides in PostgreSQL's intarray extension, specifically within the selectivity estimator function. The selectivity estimator is used by the query planner to estimate how many rows will match a given condition, helping PostgreSQL optimize query execution plans. The flaw occurs because the function fails to properly validate the type of input it receives before processing.

When a malicious user creates a database object with specially crafted input that bypasses the type validation check, they can trigger arbitrary code execution in the context of the PostgreSQL server process. Since PostgreSQL typically runs as a dedicated system user (commonly postgres), successful exploitation grants the attacker the ability to execute commands with those privileges on the underlying operating system.

The vulnerability requires the attacker to have authenticated access to the database with sufficient privileges to create objects, which somewhat limits the attack surface but still represents a significant threat in multi-tenant database environments or systems where database access is granted to less-trusted users.

Root Cause

The root cause is improper validation of input types (CWE-1287) in the intarray extension's selectivity estimator function. The function does not adequately verify that the input it receives matches expected types before processing, allowing type confusion attacks that can lead to arbitrary code execution.

Attack Vector

The attack is network-accessible and requires low-privilege authenticated access to the PostgreSQL database. An attacker with the ability to create database objects (such as functions, operators, or other schema objects) can craft malicious input that exploits the type validation flaw in the intarray extension's selectivity estimator.

The exploitation path involves:

1. Authenticating to the PostgreSQL database with object creation privileges
2. Creating a malicious database object that leverages the intarray extension
3. Triggering the selectivity estimator function with crafted input that bypasses type validation
4. Executing arbitrary code as the PostgreSQL system user

For detailed technical information, refer to the PostgreSQL Security Advisory.

Detection Methods for CVE-2026-2004

Indicators of Compromise

• Unusual object creation activity in PostgreSQL databases, particularly involving the intarray extension
• Unexpected processes spawned by the postgres system user
• Anomalous queries or function calls targeting the intarray extension's selectivity functions
• Suspicious file system activity originating from the PostgreSQL process

Detection Strategies

• Monitor PostgreSQL audit logs for unexpected DDL statements creating objects that reference the intarray extension
• Implement database activity monitoring to detect unusual query patterns involving intarray functions
• Use host-based intrusion detection to identify processes spawned by the PostgreSQL user that deviate from normal behavior
• Review database roles and permissions to identify accounts with unnecessary object creation privileges

Monitoring Recommendations

• Enable PostgreSQL logging with log_statement = 'ddl' to capture object creation events
• Deploy endpoint detection and response (EDR) solutions like SentinelOne to monitor for suspicious process execution by the database user
• Implement network segmentation to limit lateral movement if the database server is compromised
• Establish baseline behavior for database operations and alert on deviations

How to Mitigate CVE-2026-2004

Immediate Actions Required

• Upgrade PostgreSQL to patched versions: 18.2, 17.8, 16.12, 15.16, or 14.21 depending on your major version
• Review and restrict database user privileges, removing unnecessary object creation rights
• Audit the use of the intarray extension and consider disabling it if not required
• Implement network-level access controls to limit database connectivity to trusted sources

Patch Information

PostgreSQL has released security patches addressing this vulnerability. Upgrade to the following versions or later:

For complete patch details and download links, see the PostgreSQL Security Advisory.

Workarounds

• If immediate patching is not possible, revoke object creation privileges from untrusted database users
• Disable or drop the intarray extension using DROP EXTENSION intarray; if it is not required for your application
• Implement strict network access controls to limit who can connect to the PostgreSQL server
• Use PostgreSQL's row-level security and role-based access controls to minimize the attack surface

# Disable intarray extension if not needed
psql -U postgres -d your_database -c "DROP EXTENSION IF EXISTS intarray CASCADE;"

# Review users with object creation privileges
psql -U postgres -c "SELECT rolname, rolcreatedb, rolcreaterole FROM pg_roles WHERE rolcanlogin = true;"

# Restrict connection access in pg_hba.conf
# Ensure only trusted hosts can connect to the database