CVE-2026-0859: TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool

CVE-2026-0859 · Severity: medium · CVSS 4 · Published 2026-01-13

TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool

Technologies: typo3/cms-core (Packagist). Vendors: Packagist.

Quick answers

Is CVE-2026-0859 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-0859 being exploited in the wild.
How severe is CVE-2026-0859?
Medium severity, with a CVSS score of 4, published 13 January 2026.
Which products and versions are affected?
typo3/cms-core (Packagist) ECOSYSTEM:introduced=14.0.0,fixed=14.0.2.
Is there a fix for CVE-2026-0859?
Yes. typo3/cms-core (Packagist): upgrade to 14.0.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-0859?
Check whether you run typo3/cms-core (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • typo3/cms-core (Packagist): upgrade to 14.0.2 or later
    composer require typo3/cms-core:^14.0.2

Affected products

  • typo3/cms-core (Packagist) ECOSYSTEM:introduced=14.0.0,fixed=14.0.2

Identifiers

  • CVE-2026-0859
  • GHSA-7vp9-x248-9vr9

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