Bug 2538843 (CVE-2026-78030)

Summary: CVE-2026-78030 perl-DBI: DBI: Loading of arbitrary modules via unvalidated dbm_type and dbm_mldbm attributes in DBD::DBM
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in Perl DBI's bundled DBD::DBM driver. This vulnerability allows arbitrary code execution because unvalidated connection attributes, such as dbm_type and dbm_mldbm, are passed directly to Perl's module loader without verification. An attacker who can influence database connection parameters or a Data Source Name (DSN) string can exploit this flaw to load and execute arbitrary files on the system.
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Description OSIDB Bzimport 2026-09-22 20:53:27 UTC
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.