CVE-2026-6477: PostgreSQL

High severity, CVSS 8.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary-length, server-determined data into a buffer of unspecified size. Because both the \lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.

Affected products

• PostgreSQL PostgreSQL: before 14.23 (fixed in 14.23); from 15.0, before 15.18 (fixed in 15.18); from 16.0, before 16.14 (fixed in 16.14); from 17.0, before 17.10 (fixed in 17.10); from 18.0, before 18.4 (fixed in 18.4)

Published 2026-05-14. Last modified 2026-08-25.