Is CVE-2021-21365 in the CISA KEV catalog?

No. CVE-2021-21365 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21365?

CVE-2021-21365 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2021-21365?

CVE-2021-21365 has an EPSS score of 0.94% (57th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21365?

Upgrade typo3 to 11.0.3 or later.

CVE & CISA-KEV Catalog

CVE-2021-21365

MEDIUM

5.4

CVSS v3

NVD

Description

Bootstrap Package is a theme for TYPO3. It has been discovered that rendering content in the website frontend is vulnerable to cross-site scripting. A valid backend user account is needed to exploit this vulnerability. Users of the extension, who have overwritten the affected templates with custom code must manually apply the security fix. Update to version 7.1.2, 8.0.8, 9.1.4, 10.0.10 or 11.0.3 of the Bootstrap Package that fix the problem described. Updated version are available from the TYPO3 extension manager, Packagist and at https://extensions.typo3.org/extension/download/bootstrap_package/.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

typo3NVD

Affected:>= 11.0.0, < 11.0.3Fixed in:11.0.3CVE-2021-21365derived 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

0.94%probability of exploitation in 30 days

57thpercentile

Moderate risk: more likely to be exploited than 57% of all known CVEs.

References

Patch2

Exploit1

github.com

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.