CVE-2026-15043: DBI::SQL::Nano versions from 1.42 before 1.651 for Perl have inverted <= and >= SQL operators on text

[Robert Rothenberg <rrwo () cpansec org>]

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CVE-2026-15043                                       CPAN Security Group
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        CVE ID:  CVE-2026-15043
  Distribution:  DBI
      Versions:  from 1.42 before 1.651

      MetaCPAN:  https://metacpan.org/dist/DBI
      VCS Repo:  https://github.com/perl5-dbi/dbi


DBI::SQL::Nano versions from 1.42 before 1.651 for Perl have inverted
<= and >= SQL operators on text

Description
-----------
DBI::SQL::Nano versions from 1.42 before 1.651 for Perl have inverted
<= and >= SQL operators on text.

DBI::SQL::Nano, DBI's built-in mini-SQL engine, evaluated WHERE
predicates incorrectly in some cases. In the non-numeric string branch
of the is_matched method, <= was evaluated using Perl's ge operator,
and >= was evaluated using Perl's le operator.

SQL::Nano is the fallback query engine for DBI's file-backed drivers
(DBD::File, DBD::DBM, CSV-style drivers) whenever SQL::Statement is not
installed, and is forced whenever DBI_SQL_NANO=1. Queries over such
tables use these predicates directly.

The impact depends on the context. Where an application relies on a
WHERE clause to filter file-backed data for policy or authorization, an
inverted <=/>= comparison silently returns the wrong rows.

Problem types
-------------
- CWE-480 Use of Incorrect Operator

Workarounds
-----------
For deployments that cannot upgrade, apply the patch or install
SQL::Statement.


Solutions
---------
Upgrade to DBI 1.651 or later.


References
----------
https://github.com/perl5-dbi/dbi/security/advisories/GHSA-mv45-ff6j-x9jp
https://github.com/perl5-dbi/dbi/commit/e9742ef85a75867cbd696860e3bf3e32b681f98d.patch

Timeline
--------
- 2004-03-12: Version 1.42 released with DBI::SQL::Nano.
- 2026-07-10: Patch that fixes DBI::SQL::Nano merged.
- 2026-07-14: Version 1.651 released.