BIT-POSTGRESQL-2026-18024 PostgreSQL ascii() function reads past end of buffer

Buffer over-read in PostgreSQL ascii SQL function allows a user to disclose up to 3 bytes after the end of a specific allocation, via a crafted text value. This is the same class of defect that CVE-2026-2006 fixed, though this instance has less impact. Versions before PostgreSQL 18.6, 17.11, 16.1...