The php_pgsql_meta_data function in pgsql.c in the PostgreSQL (aka pgsql) extension in PHP before 5.4.42, 5.5.x before 5.5.26, and 5.6.x before 5.6.10 does not validate token extraction for table names, which might allow remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted name.  NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-1352.