The vulnerability (CVE-2026-14673) involves an untrusted search path in the PostgreSQL amcheck extension. A grantee with EXECUTE privilege on the amcheck function can set a hostile search path before invoking amcheck, enabling execution of arbitrary functions with the privileges of the owners of expression indexes dependent on the search path. This affects PostgreSQL major versions 14, 15, 16, and 18 in minor versions before 14.24, 15.19, 16.15, and 18.5 respectively. PostgreSQL 17 is unaffected.

An attacker with EXECUTE privilege on the amcheck function can escalate privileges by executing arbitrary functions as the owners of expression indexes, potentially leading to limited privilege escalation within the database environment. The CVSS score is 3.8 (low), indicating limited impact on confidentiality and integrity, with no impact on availability.

Upgrade PostgreSQL to versions 14.24, 15.19, 16.15, or 18.5 or later to address this vulnerability. Since PostgreSQL 17 is unaffected, upgrading to this version is also an option. No vendor advisory content was provided to indicate alternative mitigations or temporary fixes. Patch status is not yet confirmed in the input data; users should verify with the official PostgreSQL advisory for the latest remediation guidance.