#VU51510 Uncontrolled Recursion in TYPO3 - CVE-2021-21359

Vulnerability identifier: #VU51510

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21359

CWE-ID: CWE-674

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
TYPO3
Web applications / CMS

Vendor: TYPO3

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as an error message from another page. A remote attacker can cause a denial of service condition on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

TYPO3: 9.0.0 - 9.5.24, 10.0.0 - 11.1.0

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External links
https://typo3.org/security/advisory/typo3-core-sa-2021-005/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.