CVE-2025-12818

A vulnerability has been identified in PostgreSQL’s libpq client library, where integer wraparound in several allocation-size calculations allows a peer or input provider to cause an undersized buffer and then write out-of-bounds by hundreds of megabytes. This can lead to a client application segmentation fault or crash when using libpq to connect to a PostgreSQL server.

This issue is rated Moderate severity by Red Hat Product Security, even though it carries a High CVSS v3.1 score. The flaw resides in the libpq client library and can be triggered when a client receives specially crafted PostgreSQL protocol data that causes an integer wraparound and an out-of-bounds write. The attack complexity is Low because the malformed protocol message is processed immediately during connection, with no timing or environmental conditions required. However, the impact is limited to a denial of service of the client application only. As a result, Red Hat classifies the overall product impact as Moderate, reflecting that the flaw can interrupt client availability.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

No mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.