mailqueue TYPO3 extension affected by Insecure Deserialization in QueueableFileTransport

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.2 · 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 · score source

EPSS

• CVE-2026-0895: 0.15% estimated exploitation activity in the next 30 days; percentile 4.07 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description The extension extends TYPO3’s FileSpool component, which was vulnerable to Insecure Deserialization prior to 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. References TYPO3-EXT-SA-2026-001 https://github.com/CPS-IT/mailqueue/commit/fd09aa4e1a751551bae4b228bee814e22f2048db https://github.com/CPS-IT/mailqueue/commit/12a0a35027bb5609917790a94e43bbf117abf733

Published by the source

21 Jan 2026, 15:47 UTC

Last modified by the source

22 Jan 2026, 15:52 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-ggff-9mj3-7246

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-0895

Advisory: mailqueue TYPO3 extension affected by Insecure Deserialization in QueueableFileTransport
IDs: CVE-2026-0895, GHSA-ggff-9mj3-7246
Record: https://patchnext.com/advisories/cve-2026-0895 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: cpsit/typo3-mailqueue 0.5.1, 0.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist cpsit/typo3-mailqueue: affected < 0.4.3; >= 0.5.0, < 0.5.1; fixed in 0.4.3, 0.5.1

## Suggested inspection (read-only)
- Packagist cpsit/typo3-mailqueue: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cpsit/typo3-mailqueue.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-ggff-9mj3-7246 (GitHub-reviewed advisory GHSA-ggff-9mj3-7246 lists affected ranges: Packagist cpsit/typo3-mailqueue >=0 =0.5.0 <0.5.1)

Commands are suggestions: review each one before running it.