3.5 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:N/I:P/A:N
4.8 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
0.001 Low
EPSS
Percentile
22.7%
Date: 2021-08-11 CVE ID: CVE-2021-35955
Description
It is possible for untrusted users to inject malicious code into HTML attributes in the back end, which will be executed both in the element preview (back end) and on the website (front end).
Installations are only affected if there are untrusted back end users who have the rights to modify HTML fields (e.g. TinyMCE).
Thanks to Mikhail Khramenkov from Solar Security Research Team for reporting the issue.
Affected versions
Contao 4.0
Contao 4.1
Contao 4.2
Contao 4.3
Contao 4.4 up to 4.4.55
Contao 4.5
Contao 4.6
Contao 4.7
Contao 4.8
Contao 4.9 up to 4.9.17
Contao 4.10
Contao 4.11 up to 4.11.6
Suggested solution
Update to Contao 4.4.56, 4.9.18 or 4.11.7.
Workaround
Disable all fields that allow HTML for untrusted back end users or disable the login for these users.
More information
<https://github.com/contao/contao/security/advisories/GHSA-hr3h-x6gq-rqcp>
3.5 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:N/I:P/A:N
4.8 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
0.001 Low
EPSS
Percentile
22.7%