PostgreSQL tsvector and tsquery undersize allocations, via integer wraparound

Integer wraparound in PostgreSQL tsvector and tsquery data type functions allows an unprivileged database user to cause the server to undersize an allocation and write out-of-bounds, via crafted large inputs. This may execute arbitrary code as the operating system user running the database. These types are typically sourced from application logic, not taken from the application's user. Hence, application users attacking the database, through the application as a conduit, are unlikely. CVE-2026-6473 had fixed similar problems. Versions before PostgreSQL 18.6, 17.11, 16.15, 15.19, and 14.24 are affected.