CVE-2026-14670 in PostgreSQL
Summary
by MITRE • 08/13/2026
Heap buffer overflow in PostgreSQL plperl return of a tied hash allows the function owner to execute arbitrary code as the operating system user running the database, via a crafted function body. Versions before PostgreSQL 18.5, 17.11, 16.15, 15.19, and 14.24 are affected.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/13/2026
This heap buffer overflow vulnerability exists within PostgreSQL's plperl procedural language extension and represents a critical security flaw that allows privilege escalation through crafted perl code execution. The vulnerability specifically affects the handling of tied hashes in perl functions, where the database owner can manipulate memory allocation patterns to trigger out-of-bounds writes in heap memory structures. This type of vulnerability falls under the CWE-121 heap-based buffer overflow category and aligns with ATT&CK technique T1059.007 for script-based execution. The flaw occurs when perl functions return tied hash structures that are processed by PostgreSQL's internal memory management, creating opportunities for attackers to overwrite adjacent heap memory regions with malicious data.
The technical exploitation requires an attacker with function creation privileges to craft a perl function body that leverages the tied hash mechanism to trigger the buffer overflow condition. When PostgreSQL processes such functions, the improper bounds checking in the perl interpreter integration layer allows attackers to control memory layout and potentially execute arbitrary code with the privileges of the database operating system user. This presents a severe privilege escalation vector since the database service typically runs with elevated system permissions. The vulnerability affects multiple PostgreSQL version streams including 14 through 18, with specific patches released for versions 14.24, 15.19, 16.15, 17.11, and 18.5. The heap corruption occurs during the perl interpreter's memory management routines when processing tied hash return values, making it particularly dangerous as it can be triggered through legitimate database function execution paths.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise when attackers can leverage the elevated privileges of the database service. Attackers with minimal access rights such as function creation permissions can escalate their privileges to gain full control over the database server and potentially the underlying operating system. This type of vulnerability is particularly concerning in multi-tenant environments where database users may have different privilege levels but share the same database instance. The exploitation requires careful crafting of perl code that manipulates tied hash structures to create the precise memory layout conditions needed for heap corruption. Organizations should immediately implement mitigations including upgrading to patched versions, restricting perl function creation privileges, and monitoring for unusual perl code execution patterns in their database environments.
The vulnerability demonstrates the inherent risks of integrating interpreted languages within database systems and highlights the importance of rigorous input validation and memory safety checks in language extension interfaces. Security teams should conduct comprehensive audits of all procedural language extensions in their PostgreSQL installations to identify similar memory corruption vulnerabilities that may exist in other language handlers such as plpython or pljava. Implementation of proper access controls including role-based restrictions on function creation and execution permissions can significantly reduce the attack surface for this class of vulnerability. The ATT&CK framework's mapping to privilege escalation techniques emphasizes the need for layered defenses including database activity monitoring, regular security assessments, and maintaining up-to-date patches across all database components. Organizations should also consider implementing database firewalls and network segmentation to limit potential lateral movement if exploitation occurs.