CVE-2021-41113: Cross-Site-Request-Forgery in Backend URI Handling in Typo3
> ### Meta > CVSS: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C (8.2)
Problem It has been discovered that the new TYPO3 v11 feature that allows users to create and share deep links in the backend user interface is vulnerable to cross-site-request-forgery.
The impact is the same as described in TYPO3-CORE-SA-2020-006 (CVE-2020-11069). However, it is not limited to the same site context and does not require the attacker to be authenticated. In a worst case scenario, the attacker could create a new admin user account to compromise the system.
To successfully carry out an attack, an attacker must trick his victim to access a compromised system. The victim must have an active session in the TYPO3 backend at that time.
The following Same-Site cookie settings in $GLOBALS[TYPO3CONFVARS][BE][cookieSameSite] are required for an attack to be successful:
SameSite=strict: malicious evil.example.org invoking TYPO3 application at good.example.org SameSite=lax or none: malicious evil.com invoking TYPO3 application at example.org
Solution Update your instance to TYPO3 version 11.5.0 which addresses the problem described.
Credits Thanks to Richie Lee who reported this issue and to TYPO3 core & security team members Benni Mack and Oliver Hader who fixed the issue.
References TYPO3-CORE-SA-2021-014 CVE-2020-11069 reintroduced in TYPO3 v11.2.0
Other sources
TYPO3 is an open source PHP based web content management system released under the GNU GPL. It has been discovered that the new TYPO3 v11 feature that allows users to create and share deep links in the backend user interface is vulnerable to cross-site-request-forgery. The impact is the same as described in TYPO3-CORE-SA-2020-006 (CVE-2020-11069). However, it is not limited to the same site context and does not require the attacker to be authenticated. In a worst case scenario, the attacker could create a new admin user account to compromise the system. To successfully carry out an attack, an attacker must trick his victim to access a compromised system. The victim must have an active session in the TYPO3 backend at that time. The following Same-Site cookie settings in $GLOBALS[TYPO3CONFVARS][BE][cookieSameSite] are required for an attack to be successful: SameSite=strict: malicious evil.example.org invoking TYPO3 application at good.example.org and SameSite=lax or none: malicious evil.com invoking TYPO3 application at example.org. Update your instance to TYPO3 version 11.5.0 which addresses the problem described.
TYPO3-CORE-SA-2021-014: Cross-Site-Request-Forgery in Backend URI Handling
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
composer/typo3/cmsto a version that resolves this vulnerability.Fixed in 11.5.0 - Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 11.5.0 - Upgrade
Upgrade
TYPO3to a version that resolves this vulnerability.Fixed in 11.5.0Patch TYPO3-CORE-SA-2021-014 - Compensating control
Be aware TYPO3 backend CSRF attack success depends on SameSite settings in $GLOBALS[TYPO3_CONF_VARS][BE][cookieSameSite]; ensure vulnerable SameSite configurations are not in use (required for attack: SameSite=strict with malicious evil.example.org invoking TYPO3 at good.example.org, or SameSite=lax/none with malicious evil.com invoking TYPO3 at example.org).
Event History
Frequently Asked Questions
What is CVE-2021-41113?
CVE-2021-41113 is a Cross-Site-Request-Forgery vulnerability in TYPO3's backend URI handling.
How does CVE-2021-41113 affect TYPO3?
CVE-2021-41113 affects TYPO3 v11 versions 11.2.0 up to 11.5.0.
What is the severity of CVE-2021-41113?
CVE-2021-41113 has a severity of 8.8 (high).
How can I fix CVE-2021-41113?
To fix CVE-2021-41113, update TYPO3 to a version beyond 11.5.0 and apply the necessary patches.
Where can I find more information about CVE-2021-41113?
You can find more information about CVE-2021-41113 on the TYPO3 Security Advisory page at https://typo3.org/security/advisory/typo3-core-sa-2021-014.