CVE-2021-21359

low-risk
Published 2021-03-23

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.

Do I need to act?

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0.30% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.9/10 Medium
NETWORK / HIGH complexity

Affected Products (1)

Affected Vendors

Typo3

References (6)

Third Party Advisory https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
Release Notes https://packagist.org/packages/typo3/cms-core
Vendor Advisory https://typo3.org/security/advisory/typo3-core-sa-2021-005
Third Party Advisory https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
Release Notes https://packagist.org/packages/typo3/cms-core
Vendor Advisory https://typo3.org/security/advisory/typo3-core-sa-2021-005
24
/ 100
low-risk
Severity 18/34 · Moderate
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal