df0852fe03
While EUC_CN supports only 1- and 2-byte sequences (CS0, CS1), the mb<->wchar conversion functions allow 3-byte sequences beginning SS2, SS3. Change pg_encoding_max_length() to return 3, not 2, to close a hypothesized buffer overrun if a corrupted string is converted to wchar and back again in a newly allocated buffer. We might reconsider that in master (ie harmonizing in a different direction), but this change seems better for the back-branches. Also change pg_euccn_mblen() to report SS2 and SS3 characters as having length 3 (following the example of EUC_KR). Even though such characters would not pass verification, it's remotely possible that invalid bytes could be used to compute a buffer size for use in wchar conversion. Security: CVE-2026-2006 Backpatch-through: 14 Author: Thomas Munro <thomas.munro@gmail.com> Reviewed-by: Noah Misch <noah@leadboat.com> Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/18/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/18/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.