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CVE-2026-111879: DBI versions before 1.656 for Perl hang on a later open of a DBD::DBM table because a failed open_data does not release the table's lock

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-30
• Weakness: CWE-667

Description

DBI versions before 1.656 for Perl hang on a later open of a DBD::DBM table because a failed open_data does not release the table's lock. open_data creates the table's lock file and takes an exclusive flock on it for a CREATE, before the checks that can croak: a dbm_mldbm value that is not a module name, a failing tie, or a missing data file. The croak unwinds before the table object is blessed, so nothing releases the lock, and the meta data holding the open descriptor stays cached on the database handle. The dbm_mldbm and dbm_type values come from the DSN or the connect attributes, so a caller that chooses the serializer or the storage backend can trigger the failure. The flock has no timeout, so a later open of that table (even through a separate database handle) blocks for as long as the handle holding the stale lock lives, in the same process or any other.

Affected products

• DBI: before 1.656 — fixed in 1.656

How to fix

Upgrade to a fixed version: DBI 1.656. Check the vendor advisory for mitigations.

References

• https://github.com/perl5-dbi/dbi/commit/99bbf2ab9d137e6f042a770bd3bbba3bc0b3a901.patch
• https://github.com/perl5-dbi/dbi/security/advisories/GHSA-8cx8-9vj9-9x7j
• https://metacpan.org/release/HMBRAND/DBI-1.656/changes
• http://www.openwall.com/lists/oss-security/2026/10/20/38

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