Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🐘 Packagist

CVE-2026-0859

CVE-2026-0859 is a Deserialization of Untrusted Data vulnerability in typo3/cms-core. O3 Security confirms whether CVE-2026-0859 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool

Also known asGHSA-7vp9-x248-9vr9
Published
Jan 13, 2026
Updated
Aug 5, 2026
Affected
5 pkgs
Patched
5 / 5
Exploits
None indexed

Blast Radius

5 pkgs affected
🐘typo3/cms-core🐘typo3/cms-core🐘typo3/cms-core🐘typo3/cms-core🐘typo3/cms-core

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's mail‑file spool deserialization flaw lets local users with write access to the spool directory craft a malicious file that is deserialized during the mailer:spool:send command, enabling arbitrary PHP code execution on the web server. This issue affects TYPO3 CMS versions 10.0.0-10.4.54, 11.0.0-11.5.48, 12.0.0-12.4.40, 13.0.0-13.4.22 and 14.0.0-14.0.1.

Affected Packages

5 total 5 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagisttypo3/cms-core14.0.0&&< 14.0.214.0.2
🐘Packagisttypo3/cms-core13.0.0&&< 13.4.2313.4.23
🐘Packagisttypo3/cms-core12.0.0&&< 12.4.4112.4.41
🐘Packagisttypo3/cms-core11.0.0&&< 11.5.4911.5.49
🐘Packagisttypo3/cms-core10.0.0&&< 10.4.5510.4.55

Detection & mitigation playbook

Open-source dependency
  1. 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.

  2. Fix

    Update typo3/cms-core to 14.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-0859 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2026-0859 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-2026-0859. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

TYPO3's mail‑file spool deserialization flaw lets local users with write access to the spool directory craft a malicious file that is deserialized during the mailer:spool:send command, enabling arbitrary PHP code execution on the web server. This issue affects TYPO3 CMS versions 10.0.0-10.4.54, 11.0.0-11.5.48, 12.0.0-12.4.40, 13.0.0-13.4.22 and 14.0.0-14.0.1.
O3 Security · Impact-Aware SCA

Is CVE-2026-0859 in your dependencies?

O3 detects CVE-2026-0859 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.