UpHeron
All vulnerabilities

Servers and applications

CVE-2021-35955

Cross-site scripting via HTML attributes in the back end

Severity
Medium 4.8
Published
11 Aug 2021
Last changed
17 Jun 2026
Added to UpHeron
1 Nov 2026
Fixed in
4.4.56, 4.9.18, 4.11.7
Also known as
GHSA-hr3h-x6gq-rqcp
Sources
NVD, Project advisories (GitHub)

Description

Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field. Fixed in 4.4.56, 4.9.18, 4.11.7.

Affected software

SoftwareAffected versions
ContaoServers and applications · cpe:a:contao:contao
  • From 4.0.0 before 4.4.56
  • From 4.5.0 before 4.9.18
  • From 4.10.0 before 4.11.7
ContaoServers and applications · github:contao/contao
  • From 4.0.0 before 4.4.56

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-35955
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-35955
  • GitHub Advisory Database https://github.com/advisories/GHSA-hr3h-x6gq-rqcp
  • github.com https://github.com/contao/contao/security/advisories/GHSA-hr3h-x6gq-rqcp