What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-13 · updated 2026-06-17
• Weakness: CWE-502

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 products

• typo3: from 10.0.0 before 10.4.55; from 11.0.0 before 11.5.49; from 12.0.0 before 12.4.41; from 13.0.0 before 13.4.23; from 14.0.0 before 14.0.2 — fixed in 10.4.55, 11.5.49, 12.4.41, 13.4.23, 14.0.2

How to fix

Upgrade to a fixed version: typo3 10.4.55, 11.5.49, 12.4.41, 13.4.23. Check the vendor advisory for mitigations.

References

• https://github.com/TYPO3/typo3/commit/3225d705080a1bde57a66689621c947da5a4782f
• https://github.com/TYPO3/typo3/commit/722bf71c118b0a8e4f2c2494854437d846799a13
• https://github.com/TYPO3/typo3/commit/e0f0ceee480c203fbb60b87454f5f193e541d27f
• https://typo3.org/security/advisory/typo3-core-sa-2026-004

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