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

> Attackers can execute arbitrary code via insecure deserialization in the Mailqueue extension, which overrides core security fixes.

- **Severity:** Medium 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Jan 2026
- **Updated:** 20 Jan 2026
- **Also known as:** GHSA-ggff-9mj3-7246

## What is CVE-2026-0895?

CVE-2026-0895 is a medium-severity unsafe deserialization vulnerability in TYPO3 Extension "Mailqueue", published on 20 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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 .

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-0895?

4 open source packages ship an affected version, including cpsit/typo3-mailqueue.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cpsit/typo3-mailqueue` | Packagist | All versions | 0.4.3 |
| `cpsit/typo3-mailqueue` | Packagist | All versions | 0.4.3 |
| `cpsit/typo3-mailqueue` | Packagist | From 0.5.0 | 0.5.1 |
| `cpsit/typo3-mailqueue` | Packagist | From 0.5.0 | 0.5.1 |

## How do I fix CVE-2026-0895?

Upgrade cpsit/typo3-mailqueue to a fixed version for your release line: 0.4.3 or 0.5.1.

## Is CVE-2026-0895 being exploited?

There is no known exploitation of CVE-2026-0895 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-0895 and fix it if it is affected.

What it is: CVE-2026-0895 is a medium-severity unsafe deserialization vulnerability in TYPO3 Extension "Mailqueue", published on 20 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-0895 in the wild and no public exploit code.

Affected packages and fixed versions:
- cpsit/typo3-mailqueue (Packagist): affected all versions; fixed in 0.4.3
- cpsit/typo3-mailqueue (Packagist): affected all versions; fixed in 0.4.3
- cpsit/typo3-mailqueue (Packagist): affected from 0.5.0; fixed in 0.5.1
- cpsit/typo3-mailqueue (Packagist): affected from 0.5.0; fixed in 0.5.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-0895/ (Markdown: https://insights.sbomify.com/CVE-2026-0895/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-0895
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-0895
- OSV: https://osv.dev/vulnerability/CVE-2026-0895

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-0895/
Summaries are generated and may contain mistakes; the official description above is the record.