How severe is CVE-2016-4056?

CVE-2016-4056 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2016-4056?

CVE-2016-4056 affects the following packages: typo3/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2016-4056?

Update typo3/cms to 6.2.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-4056 is resolved across your whole dependency graph.

How do I detect CVE-2016-4056 in my Packagist dependencies?

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

How do I mitigate CVE-2016-4056 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 CVE-2016-4056 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2016-4056, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2016-4056?

CVE-2016-4056 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 65th 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 CVE-2016-4056?

CVE-2016-4056 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 CVE-2016-4056 published, and has it been updated?

CVE-2016-4056 was published on January 23, 2017 and was last updated on October 24, 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

CVE-2016-4056 — cms

MEDIUM

CVE-2016-4056 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in typo3/cms. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for typo3/cms — see the affected versions and patch details below.

TYPO3 Backend component Cross-site scripting (XSS) vulnerability

Also known asGHSA-ffcm-vhcw-p32r

Published

Jan 23, 2017

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs65th percentile — riskier than 65% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐘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

Cross-site scripting (XSS) vulnerability in the Backend component in TYPO3 6.2.x before 6.2.19 allows remote attackers to inject arbitrary web script or HTML via the module parameter when creating a bookmark.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`typo3/cms`	≥ 6.2.0&&< 6.2.19	6.2.19`composer require typo3/cms:^6.2.19`

Affected Products

1 product · 32 configurations

Application

typo3typo3

20 versions

6.26.2.06.2.16.2.26.2.36.2.46.2.56.2.66.2.76.2.86.2.96.2.10

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Cross-site scripting (XSS) vulnerability in the Backend component in TYP…

labs.integrity.ptNVDJan 2017

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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/cms to 6.2.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-4056 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

O3 Security · Impact-Aware SCA

Is CVE-2016-4056 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template or Metasploit module yet. 1 public proof-of-concept reference is listed on this page.

Timeline

Disclosed

Jan 23, 2017

First exploit

Jan 24, 2017

1 day after disclosure — rapid exploitation

Last updated

Oct 24, 2026

Identifiers

CVE-2016-4056

GHSA-ffcm-vhcw-p32r

References

Advisorynvd.nist.gov · CVE 2016 4056 Fixtypo3.org · typo3 core sa 2016 006 Articleopenwall.com Weblabs.integrity.pt · cve pending stored cross site scripting in typo3 bookmarks Webtypo3.org · typo3 core sa 2016 006 Packagegithub.com · typo3 Evidencelabs.integrity.pt · cve pending stored cross site scripting in typo3 bookmarks

Related vulnerabilities

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

GHSA-2rcw-9hrm-8q7qGHSA-4h5c-5g25-v7fhGHSA-6487-3qvg-8px9GHSA-772m-43f3-hmf8GHSA-7q33-hxwj-7p8vGHSA-85ch-44w7-rf32GHSA-8h4m-r4wm-xj7rGHSA-8m6j-p5jv-v69w

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026