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Vulnerabilities

Vulnerability · CVE-2021-21365

Bootstrap Package is a theme for TYPO3.

Published Apr 27, 2021 · catalog updated Jun 17, 2026 · Bootstrap Package is a

Last checked Nov 4, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-21365. EPSS is 0.94%. Act only if a listed version of Bootstrap Package is a is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Bootstrap Package is a).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.94%
Remediation
Version ranges on file
Affected products
cpe typo3/typo3

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/.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe typo3/typo3< 10.0.10
  • cpe typo3/typo3< 11.0.3
  • cpe typo3/typo3< 7.1.2
  • cpe typo3/typo3< 8.0.8
  • cpe typo3/typo3< 9.0.4
  • cpe typo3/typo3< 9.1.3

How to fix CVE-2021-21365

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-21365. EPSS is 0.94%. Act only if a listed version of Bootstrap Package is a is installed.

Which versions are affected?

Compare what you have installed with < 10.0.10, < 11.0.3, < 7.1.2, < 8.0.8, < 9.0.4, < 9.1.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.94%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

TYPO3 security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 27, 2021 · Monitored products — high

    Detected

    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 o

  2. Jun 17, 2026 · Monitored products — high

    Updated

    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 o

Sources

  • CVE.orgVulnerability recordCVE-2021-21365

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2021-21365

    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 o

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 4, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • Monitored products — highNov 4, 2026