Vulnerability in Typo3

CVE-2021-21359

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.25, 10.4.14, 11.1.1 requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded. This is fixed in versions 9.5.25, 10.4.14, 11.1.1.

EPSS: 0.017 (75.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-21359?
CVE-2021-21359 is a medium-severity vulnerability in Typo3, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 5.9/10. Published 2021-03-23.
How severe is CVE-2021-21359?
Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2021-21359 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.