How severe is CVE-2019-12747?

CVE-2019-12747 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2019-12747?

CVE-2019-12747 affects the following packages: typo3/cms-core (Packagist), typo3/cms-core (Packagist), typo3/cms (Packagist), typo3/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2019-12747?

Update typo3/cms-core to 8.7.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-12747 is resolved across your whole dependency graph.

How do I detect CVE-2019-12747 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/cms-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2019-12747 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.

How does O3 Security protect against CVE-2019-12747?

O3 pinpoints whether CVE-2019-12747 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2019-12747 actively exploited in the wild?

No public exploit code has been indexed for CVE-2019-12747 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 type of vulnerability is CVE-2019-12747?

CVE-2019-12747 is classified as Deserialization of Untrusted Data (CWE-502). 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-2019-12747 published, and has it been updated?

CVE-2019-12747 was published on July 9, 2019 and was last updated on August 4, 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

CVE-2019-12747

HIGH

CVE-2019-12747 is a high-severity (CVSS 8.8) Deserialization of Untrusted Data vulnerability in typo3/cms-core. O3 Security confirms whether CVE-2019-12747 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

TYPO3 Vulnerable to Insecure Deserialization

Also known asGHSA-86hp-xrhj-fhpq

Published

Jul 9, 2019

Updated

Aug 4, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Blast Radius

4 pkgs affected

🐘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

TYPO3 8.x through 8.7.26 and 9.x through 9.5.7 allows Deserialization of Untrusted Data.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`typo3/cms-core`	≥ 8.0.0&&< 8.7.27	8.7.27
🐘Packagist	`typo3/cms-core`	≥ 9.0.0&&< 9.5.8	9.5.8
🐘Packagist	`typo3/cms`	≥ 8.0.0&&< 8.7.27	8.7.27
🐘Packagist	`typo3/cms`	≥ 9.0.0&&< 9.5.8	9.5.8

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-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update typo3/cms-core to 8.7.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-12747 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.
How O3 protects you
O3 pinpoints whether CVE-2019-12747 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2019-12747. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

TYPO3 8.x through 8.7.26 and 9.x through 9.5.7 allows Deserialization of Untrusted Data.

O3 Security · Impact-Aware SCA

Is CVE-2019-12747 in your dependencies?

O3 detects CVE-2019-12747 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works