- Component Type: TYPO3 CMS
- Vulnerable subcomponent: Backend API (ext:backend)
- Release Date: June, 25th
- Vulnerability Type: Arbitrary Code Execution, Cross-Site Scripting
- Affected Versions: 8.0.0-8.7.26 and 9.0.0-9.5.7
- Severity: Medium
- Suggested CVSS v3.0: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C/CR:X/IR:X/AR:X/MAV:X/MAC:X/MPR:H/MUI:X/MS:X/MC:X/MI:X/MA:X
- CVE: not assigned yet
Backend API configuration using Page TSconfig is vulnerable to arbitrary code execution and cross-site scripting. TSconfig fields of page properties in backend forms can be used to inject malicious sequences. Field tsconfig_includes is vulnerable to directory traversal leading to same scenarios as having direct access to TSconfig settings.
A valid backend user account having access to modify values for fields pages.TSconfig and pages.tsconfig_includes is needed in order to exploit this vulnerability.
Update to TYPO3 versions 8.7.27 or 9.5.8 that fix the problems described. Fields pages.TSconfig and pages.tsconfig_includes are denied of being modified by non-admin users.
Thanks to Benjamin Kott and Oliver Hader who reported this issue and to TYPO3 core team member Andreas Fernandez who fixed the issue.
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