TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool

CVE-2026-0859 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Problem

Local platform users who can write to TYPO3’s mail‑file spool directory can craft a file that the system will automatically deserialize without any class restrictions. This flaw allows an attacker to inject and execute arbitrary PHP code in the public scope of the web server.

The vulnerability is triggered when TYPO3 is configured with $GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport_spool_type'] = 'file'; and a scheduler task or cron job runs the command mailer:spool:send. The spool‑send operation performs the insecure deserialization that is at the core of this issue.

Solution

Update to TYPO3 versions 10.4.55 ELTS, 11.5.49 ELTS, 12.4.41 LTS, 13.4.23 LTS, 14.0.2 that fix the problem described.

Credits

Thanks to Vitaly Simonovich for reporting this issue, and to TYPO3 security team members Elias Häußler and Oliver Hader for fixing it.

References

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-01-13 21:54:06 UTC
Updated
2026-01-13 21:54:10 UTC
GitHub reviewed
2026-01-13 21:54:06 UTC
NVD published
2026-01-13

EPSS Score

Score Percentile
0.04% 11.72%

CVSS Scores

Base score Version Severity Vector
5.2 4.0 —
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H Click to expand
Attack vector (AV:L)
Attacker needs local access on the target system.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:H)
High confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:H)
High integrity impact on subsequent systems.
Subsequent system availability impact (SA:H)
High availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-7vp9-x248-9vr9 ↗
CVE CVE-2026-0859 ↗

CWEs

CWE id Name
CWE-502 Deserialization of Untrusted Data

Credits

  • eliashaeussler (remediation_developer)
  • ohader (remediation_developer)

Affected packages (5)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer typo3/cms-core >= 14.0.0, <= 14.0.1 14.0.2 —
composer typo3/cms-core >= 13.0.0, <= 13.4.22 13.4.23 —
composer typo3/cms-core >= 12.0.0, <= 12.4.40 12.4.41 —
composer typo3/cms-core >= 11.0.0, <= 11.5.48 11.5.49 —
composer typo3/cms-core >= 10.0.0, <= 10.4.54 10.4.55 —

References

cvelogic Threat Intelligence