It has been discovered that backend user settings (in $BE_USER->uc) are vulnerable to insecure deserialization. In combination with vulnerabilities of 3rd party components this can lead to remote code execution. A valid backend user account is needed to exploit this vulnerability.

Update to TYPO3 versions 9.5.17 or 10.4.2 that fix the problem described.

References

• https://typo3.org/security/advisory/typo3-core-sa-2020-005

References

• GHSA-2wj9-434x-9hvp
• https://nvd.nist.gov/vuln/detail/CVE-2020-11067
• https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2020-11067.yaml
• https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2020-11067.yaml
• https://typo3.org/security/advisory/typo3-core-sa-2020-005