What is CVE-2026-0859?

CVE-2026-0859 is a high-severity vulnerability in Typo3, classified under Deserialization of Untrusted Data. CVSS score: 7.8/10. Published 2026-01-13.

How severe is CVE-2026-0859?

High severity. CVSS v3 base score is 7.8 out of 10.

Deserialization in Typo3

CVE-2026-0859

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 serve…

Vulnerability class: Insecure Deserialization

EPSS: 0.002 (6.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Typo3
Typo3 Cms — versions 10.0.0, 11.0.0, 12.0.0

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

f4fb688c-4412-4426-b4b8-421ecf27b14a (vendor-advisory, Vendor Advisory)
f4fb688c-4412-4426-b4b8-421ecf27b14a (Patch, patch)
f4fb688c-4412-4426-b4b8-421ecf27b14a (Patch, patch)
f4fb688c-4412-4426-b4b8-421ecf27b14a (Patch, patch)

Frequently asked questions

What is CVE-2026-0859?: CVE-2026-0859 is a high-severity vulnerability in Typo3, classified under Deserialization of Untrusted Data. CVSS score: 7.8/10. Published 2026-01-13.
How severe is CVE-2026-0859?: High severity. CVSS v3 base score is 7.8 out of 10.