DEBIAN-CVE-2026-78030

DBI versions before 1.653 for Perl load arbitrary modules via unvalidated dbmtype and dbmmldbm attributes in DBD::DBM.  DBD::DBM passes the dbmtype and dbmmldbm connect attributes to require without checking that the value names a module. require treats a path-shaped string as a literal filename and does not consult @INC, so the attribute chooses the file that Perl loads and runs.  The MLDBM::Serializer:: prefix that DBD::DBM prepends to dbmmldbm is not a boundary: only the :: separators are rewritten to /, so a value containing / traverses out of the serializer directory. The value is also assigned to $MLDBM::Serializer, which MLDBM requires the same way when it ties the table.  A caller that lets an untrusted party influence either attribute, for example through a DSN fragment or a parameter that selects a storage backend, runs the file-scope code of whatever module the value names.  For example,      my $dsn = "dbi:DBM:fdir=/var/db;dbm_type=../../Untrusted.pm"     my $dbh = DBI->connect( $dsn );  Note that DBD::Gofer forwards connect attributes to the server side, and DBI::ProxyServer checks only that a DSN starts with a driver prefix.