Is CVE-2021-21359 in the CISA KEV catalog?

No. CVE-2021-21359 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21359?

CVE-2021-21359 has a CVSS v3 base score of 5.9 (MEDIUM).

What is the EPSS score for CVE-2021-21359?

CVE-2021-21359 has an EPSS score of 1.73% (75th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21359?

Upgrade typo3 to 11.1.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-21359

MEDIUMEPSS 75th pctl

5.9

CVSS v3

NVD

Description

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.

CWE-405 CWE-674

How to fix

Remediation Available

typo3NVD

Affected:>= 11.0.0, < 11.1.1Fixed in:11.1.1CVE-2021-21359derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

1.73%probability of exploitation in 30 days

75thpercentile

Elevated risk: more likely to be exploited than 75% of all known CVEs.

References

Vendor Advisory1

typo3.org

Third-Party Advisory2

Related Vulnerabilities

Other CWE-405 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-11187	High	7.5	15%	-	Fix
CVE-2025-8677	High	7.5	11%	-	Fix
CVE-2021-38447	High	8.6	2.1%	-	Fix
CVE-2018-15492	High	7.5	1.2%	-	-
CVE-2024-34702	Medium	5.3	0.8%	-	Fix

Embed a live status badge for CVE-2021-21359

Markdown

[![CVE-2021-21359](https://tridentstack.com/cve/badge/CVE-2021-21359.svg)](https://tridentstack.com/cve/CVE-2021-21359)

HTML

<a href="https://tridentstack.com/cve/CVE-2021-21359"><img src="https://tridentstack.com/cve/badge/CVE-2021-21359.svg" alt="CVE-2021-21359"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it works Start freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.