CVE-2026-126663

Description

Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6 contains a path traversal vulnerability that allows content editors to read image files anywhere on the filesystem via the { {image::} } insert tag. Attackers can embed percent-encoded sequences like ..%2f that pass Validator::isInsecurePath() before rawurldecode(), making the frontend resize and serve readable image files outside the files directory.

References

• https://github.com/contao/contao/blob/5.3.53/core-bundle/src/InsertTag/Resolver/LegacyInsertTag.php#L565-L582
• https://github.com/contao/contao/commit/0f7989eb5b28d85dcd441ef22f80f8af4f56433e
• https://github.com/contao/contao/commit/688c0f6213afbd000cd22ad0a44555eca80b40ab
• https://github.com/contao/contao/commit/e820e3c9d79a5c07f274558513c8db08a79bf804
• https://github.com/contao/contao/releases/tag/5.3.54