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.
Published: 2026-09-19
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

Vendor Solution

Upgrade to DBI version 1.653 or later, or apply the upstream patch.

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History

Sat, 19 Sep 2026 11:00:00 +0000

Type Values Removed Values Added
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.
Title DBI versions before 1.653 for Perl load arbitrary modules via unvalidated dbm_type and dbm_mldbm attributes in DBD::DBM
Weaknesses CWE-470
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-09-19T10:45:10.164Z

Reserved: 2026-08-22T00:39:23.300Z

Link: CVE-2026-78030

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-19T11:16:37.667

Modified: 2026-09-19T11:16:37.667

Link: CVE-2026-78030

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses