setup_regexp_matches() sizes the buffer used to convert matched substrings back from pg_wchar form at the smaller of maxlen*eml and the original string's byte length, on the assumption that such a conversion cannot produce more bytes than the string it came from. That assumption holds only for validly encoded input. But pg_mb2wchar_with_len() silently accepts bytes that are invalid in the database encoding, turning each such byte into one pg_wchar, and converting that back can take more bytes than the input did. A string made of such bytes therefore overruns the conversion buffer by up to its own length, corrupting the following memory. regexp_match(), regexp_matches(), regexp_split_to_table() and regexp_split_to_array() are all affected. Fix by dropping the tighter bound and always allocating maxlen*eml + 1 bytes. Reported-by: Francesco Verardi <frevadiscor89@gmail.com> Author: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Backpatch-through: 14 Security: CVE-2026-14664
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/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/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/.