CVE-2026-78030DBI versions before 1.653 for Perl load arbitrary modules via unvalidated dbm_type and dbm_mldbm attributes in DBD::DBM

Official description

DBI versions before 1.653 for Perl load arbitrary modules via unvalidated dbm_type and dbm_mldbm attributes in DBD::DBM. DBD::DBM passes the dbm_type and dbm_mldbm 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 dbm_mldbm 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:f_dir=/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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://metacpan.org/release/HMBRAND/DBI-1.653/changes release-notes
• https://github.com/perl5-dbi/dbi/commit/315c6ce703b8b3cbe9188062d9ec80730293554a.patch patch
• https://github.com/perl5-dbi/dbi/security/advisories/GHSA-wqmw-wqwx-3fr7 vendor-advisory
• http://www.openwall.com/lists/oss-security/2026/09/19/4