Is CVE-2021-21370 in the CISA KEV catalog?

No. CVE-2021-21370 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21370?

CVE-2021-21370 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2021-21370?

CVE-2021-21370 has an EPSS score of 0.87% (54th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21370?

Upgrade typo3 to 11.1.1 or later.

CVE & CISA-KEV Catalog

CVE-2021-21370

MEDIUM

5.4

CVSS v3

NVD

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that content elements of type _menu_ are vulnerable to cross-site scripting when their referenced items get previewed in the page module. A valid backend user account is needed to exploit this vulnerability. This is fixed in versions 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

typo3NVD

Affected:>= 11.0.0, < 11.1.1Fixed in:11.1.1CVE-2021-21370derived from NVD

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 ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Exploit Intelligence

0.87%probability of exploitation in 30 days

54thpercentile

Moderate risk: more likely to be exploited than 54% of all known CVEs.

References

Vendor Advisory1

typo3.org

Third-Party Advisory2

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

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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.