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

Source: https://junglewise.ai/threats/cve-2026-0859-typo3-cms-allows-insecure-deserialization-via-mailer-file-spool  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-01-13  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/typo3-cms-core). Vendors: [Packagist](https://junglewise.ai/threats/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

  ```sh
  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

## Related threats

- [The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 became ineffective in TYPO3 v13.0, where TYPO3 CMS started](https://junglewise.ai/threats/cve-2026-19418-typo3-cms-broken-access-control-in-backend-and-install-tool)
- [TYPO3 CMS broken access control in Media Module](https://junglewise.ai/threats/cve-2026-49742-typo3-cms-broken-access-control-in-media-module)
- [TYPO3 CMS broken access control in Form Framework form_definition table](https://junglewise.ai/threats/cve-2026-49741-typo3-cms-broken-access-control-in-form-framework-form-definition)
- [TYPO3 CMS insecure deserialization in VariableFrontend and Registry](https://junglewise.ai/threats/cve-2026-49740-typo3-cms-insecure-deserialization-in-variablefrontend-and)
- [TYPO3 CMS path traversal in GeneralUtility::isAllowedAbsPath](https://junglewise.ai/threats/cve-2026-49738-typo3-cms-path-traversal-in-generalutility-isallowedabspath)