CVE-2026-54760: Langroid: SQLChatAgent dangerous-function blocklist can be bypassed with quoted or schema-qualified pg_read_file calls

The SQLChatAgent SQL-injection mitigation, with default allow_dangerous_operations=False, combines a raw-text regex blocklist (_DANGEROUS_SQL_PATTERNS) with a sqlglot SELECT-only statement allowlist. The blocklist entries that target callable functions require the function name to be immediately followed by \s*\(.

PostgreSQL accepts the same call with the name separated from ( by a quoted identifier, an inline comment, or schema qualification. These forms evade the regex, still parse as SELECT, and execute the same PostgreSQL function. This restores the pg_read_file server-side file-read primitive that the prior CVE-2026-25879 / GHSA-pmch-g965-grmr fix was meant to block: the parent advisory fixed a missing pg_read_file blocklist entry, while this report shows that the added regex is bypassable.