CVE-2026-126663

EUVD-2026-123405
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
4.3 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
contaocontao
4.0.0 ≤
𝑥
< 5.3.54
CNA
contaocontao
𝑥
< 5.7.17
CNA
contaocontao
𝑥
< 6.0.6
CNA
Common Weakness Enumeration
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
https://github.com/contao/contao/releases/tag/5.7.17
https://github.com/contao/contao/releases/tag/6.0.6
https://github.com/contao/contao/security/advisories/GHSA-r7cf-mfp4-r23h
https://www.vulncheck.com/advisories/contao-4.0.0-before-5.3.54-5.4.0-before-5.7.17-and-6.0.0-before-6.0.6-path-traversal-via-image-insert-tag