How severe is CVE-2016-5091?

CVE-2016-5091 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2016-5091?

CVE-2016-5091 affects the following packages: typo3/cms-extbase (Packagist), typo3/cms-extbase (Packagist), typo3/cms-extbase (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2016-5091?

Update typo3/cms-extbase to 6.2.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-5091 is resolved across your whole dependency graph.

How do I detect CVE-2016-5091 in my Packagist dependencies?

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

How do I mitigate CVE-2016-5091 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2016-5091 actively exploited in the wild?

No public exploit code has been indexed for CVE-2016-5091 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 CVE-2016-5091?

CVE-2016-5091 has an EPSS (Exploit Prediction Scoring System) score of 3.4%, placing it in the 89th 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-2016-5091?

CVE-2016-5091 is classified as CWE-254 (CWE-254). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2016-5091 published, and has it been updated?

CVE-2016-5091 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

HIGH severity

CVE-2016-5091 — cms-extbase

HIGH

CVE-2016-5091 is a high-severity (CVSS 8.1) CWE-254 vulnerability in typo3/cms-extbase. A fix is available for typo3/cms-extbase — see the affected versions and patch details below.

Extbase for TYPO3 allows RCE

Also known asGHSA-jxg5-35fj-ccwf

Published

Jan 23, 2017

Updated

Oct 24, 2026

Affected

3 pkgs

Patched

2 / 3

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.4%probability of exploitation in next 30 days

Lower Risk+0.80%

Lower risk than most CVEs89th percentile — riskier than 89% 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

3 pkgs affected

🐘typo3/cms-extbase🐘typo3/cms-extbase🐘typo3/cms-extbase

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

Extbase in TYPO3 4.3.0 before 6.2.24, 7.x before 7.6.8, and 8.1.1 allows remote attackers to obtain sensitive information or possibly execute arbitrary code via a crafted Extbase action.

Affected Packages

3 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`typo3/cms-extbase`	all versions	6.2.24`composer require typo3/cms-extbase:^6.2.24`
🐘Packagist	`typo3/cms-extbase`	≥ 7.0&&< 7.6.8	7.6.8`composer require typo3/cms-extbase:^7.6.8`
🐘Packagist	`typo3/cms-extbase`	all versions	No fix

Affected Products

1 product · 19 configurations

Application

typo3typo3

≤ 6.2.23

18 versions

7.0.07.0.27.1.07.2.07.3.07.3.17.4.07.5.07.6.07.6.17.6.27.6.3

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-extbase, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/cms-extbase to 6.2.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-5091 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Extbase in TYPO3 4.3.0 before 6.2.24, 7.x before 7.6.8, and 8.1.1 allows remote attackers to obtain sensitive information or possibly execute arbitrary code via a crafted Extbase action.

O3 Security · Impact-Aware SCA

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