CVE-2021-37627: Privilege escalation via form generator
Impact
It is possible for untrusted users to gain administrator rights with the form generator.
Installations are only affected if there are untrusted back end users with access to the form generator.
Patches
Update to Contao 4.4.56, 4.9.18 or 4.11.7.
Workarounds
Disable the form generator or disable the login for untrusted back end users.
References
https://contao.org/en/security-advisories/privilege-escalation-with-the-form-generator
For more information
If you have any questions or comments about this advisory, open an issue in contao/contao.
Other sources
Contao is an open source CMS that allows creation of websites and scalable web applications. In affected versions it is possible to gain privileged rights in the Contao back end. Installations are only affected if they have untrusted back end users who have access to the form generator. All users are advised to update to Contao 4.4.56, 4.9.18 or 4.11.7. As a workaround users may disable the form generator or disable the login for untrusted back end users.
Privilege escalation with the form generator
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
composer/contao/contaoto a version that resolves this vulnerability.Fixed in 4.11.7 - Upgrade
Upgrade
composer/contao/contaoto a version that resolves this vulnerability.Fixed in 4.9.18 - Upgrade
Upgrade
composer/contao/contaoto a version that resolves this vulnerability.Fixed in 4.4.56 - Upgrade
Upgrade
composer/contao/core-bundleto a version that resolves this vulnerability.Fixed in 4.11.7 - Upgrade
Upgrade
composer/contao/core-bundleto a version that resolves this vulnerability.Fixed in 4.9.18 - Upgrade
Upgrade
composer/contao/core-bundleto a version that resolves this vulnerability.Fixed in 4.4.56 - Upgrade
Upgrade
contao/contaoto a version that resolves this vulnerability.Fixed in 4.4.56 - Upgrade
Upgrade
contao/contaoto a version that resolves this vulnerability.Fixed in 4.9.18 - Upgrade
Upgrade
contao/contaoto a version that resolves this vulnerability.Fixed in 4.11.7 - Configuration
As a workaround, disable the form generator to prevent untrusted back end users from gaining privileged/administrator rights.
Contao form generator form generator = disabled - Configuration
As a workaround, disable login for untrusted back end users so they cannot access the form generator.
Contao back end login for untrusted users login for untrusted back end users = disabled
Event History
Frequently Asked Questions
What is CVE-2021-37627?
CVE-2021-37627 is a vulnerability in Contao CMS that allows for privilege escalation in the Contao back end through the form generator.
How does CVE-2021-37627 affect Contao CMS?
CVE-2021-37627 affects Contao CMS installations if they have untrusted back end users who have access to the form generator.
What is the severity of CVE-2021-37627?
CVE-2021-37627 has a severity rating of 7.2 (high).
How can I fix CVE-2021-37627?
To fix CVE-2021-37627, you should update Contao CMS to a version beyond the affected range.
Where can I find more information about CVE-2021-37627?
More information about CVE-2021-37627 can be found at the following links: [Contao Security Advisories](https://contao.org/en/security-advisories/privilege-escalation-with-the-form-generator.html) and [GitHub Security Advisory](https://github.com/contao/contao/security/advisories/GHSA-hq5m-mqmx-fw6m).