Affected: DBI

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: Ubuntu:Pro:14.04:LTS: libdbi-perl, Ubuntu:Pro:16.04:LTS: libdbi-perl, Ubuntu:Pro:18.04:LTS: libdbi-perl, Ubuntu:Pro:20.04:LTS: libdbi-perl, Ubuntu:22.04:LTS: libdbi-perl, Ubuntu:24.04:LTS: libdbi-perl, Ubuntu:26.04:LTS: libdbi-perl

Harsh Raj Singhania discovered that the Perl DBI module did not correctly validate certain attributes. An attacker could possibly use this issue to execute arbitrary code. (CVE-2026-78030)

Harsh Raj Singhania discovered that the Perl DBI module did not correctly handle certain string operations. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-88816)