How severe is GHSA-fjh3-g8gq-9q92?

GHSA-fjh3-g8gq-9q92 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-fjh3-g8gq-9q92?

GHSA-fjh3-g8gq-9q92 affects the following packages: typo3/cms-backend (Packagist), typo3/cms-backend (Packagist), typo3/cms-core (Packagist), typo3/cms-core (Packagist), typo3/cms (Packagist), typo3/cms (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-fjh3-g8gq-9q92?

Update typo3/cms-backend to 10.4.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fjh3-g8gq-9q92 is resolved across your whole dependency graph.

How do I detect GHSA-fjh3-g8gq-9q92 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/cms-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-fjh3-g8gq-9q92 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is GHSA-fjh3-g8gq-9q92 actively exploited in the wild?

No public exploit code has been indexed for GHSA-fjh3-g8gq-9q92 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-fjh3-g8gq-9q92?

GHSA-fjh3-g8gq-9q92 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 58th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-fjh3-g8gq-9q92?

GHSA-fjh3-g8gq-9q92 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-fjh3-g8gq-9q92 published, and has it been updated?

GHSA-fjh3-g8gq-9q92 was published on March 23, 2021 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

Cross-Site Scripting in Content PreviewGHSA-fjh3-g8gq-9q92

MEDIUM

GHSA-fjh3-g8gq-9q92 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in typo3/cms-backend. A fix is available for typo3/cms-backend — see the affected versions and patch details below.

Also known asBIT-typo3-2021-21340CVE-2021-21340

Published

Mar 23, 2021

Updated

Jul 8, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs58th percentile — riskier than 58% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-fjh3-g8gq-9q92 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

6 pkgs affected

🐘typo3/cms-backend🐘typo3/cms-backend🐘typo3/cms-core🐘typo3/cms-core🐘typo3/cms🐘typo3/cms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Problem

It has been discovered that database fields used as descriptionColumn are vulnerable to cross-site scripting when their content gets previewed in the page module. A valid backend user account is needed to exploit this vulnerability.

Solution

Update to TYPO3 versions 10.4.14, 11.1.1 that fix the problem described.

Credits

Thanks to Richie Lee who reported this issue and to TYPO3 framework merger Andreas Fernandez who fixed the issue.

References

TYPO3-CORE-SA-2021-007

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`typo3/cms-backend`	≥ 10.0.0&&< 10.4.14	10.4.14`composer require typo3/cms-backend:^10.4.14`
🐘Packagist	`typo3/cms-backend`	≥ 11.0.0&&< 11.1.1	11.1.1`composer require typo3/cms-backend:^11.1.1`
🐘Packagist	`typo3/cms-core`	≥ 10.0.0&&< 10.4.14	10.4.14`composer require typo3/cms-core:^10.4.14`
🐘Packagist	`typo3/cms-core`	≥ 11.0.0&&< 11.1.1	11.1.1`composer require typo3/cms-core:^11.1.1`
🐘Packagist	`typo3/cms`	≥ 10.0.0&&< 10.4.14	10.4.14`composer require typo3/cms:^10.4.14`
🐘Packagist	`typo3/cms`	≥ 11.0.0&&< 11.1.1	11.1.1`composer require typo3/cms:^11.1.1`

Affected Products

1 product · 2 configurations

Application

typo3typo3

≥ 11.0.0 && < 11.1.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/cms-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/cms-backend to 10.4.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fjh3-g8gq-9q92 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Problem It has been discovered that database fields used as _descriptionColumn_ are vulnerable to cross-site scripting when their content gets previewed in the page module. A valid backend user account is needed to exploit this vulnerability. ### Solution Update to TYPO3 versions 10.4.14, 11.1.1 that fix the problem described. ### Credits Thanks to Richie Lee who reported this issue and to TYPO3 framework merger Andreas Fernandez who fixed the issue. ### References * [TYPO3-CORE-SA-2021-007](https://typo3.org/security/advisory/typo3-core-sa-2021-007)

O3 Security · Impact-Aware SCA

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CVSS Score

5.4/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

TYPO3.CMS

6.0/10

Code-Review10/10

Maintained10/10

Branch-Protection0/10

Assessed Oct 5, 2026

Timeline

Disclosed

Mar 23, 2021

Last updated

Jul 8, 2026

Identifiers

GHSA-fjh3-g8gq-9q92

BIT-typo3-2021-21340

References

Advisorynvd.nist.gov Webgithub.com Webgithub.com Webgithub.com Webpackagist.org Webtypo3.org

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting typo3/cms-backend are rated as high or higher (top: high).

CVE-2026-19418CVE-2026-47352CVE-2026-47351CVE-2026-6553CVE-2025-59020CVE-2025-59017CVE-2025-59019CVE-2025-59014

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 8, 2026

Cross-Site Scripting in Content PreviewGHSA-fjh3-g8gq-9q92

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Problem

Solution

Credits

References

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is GHSA-fjh3-g8gq-9q92 in your dependencies?