# CVE-2026-0859: TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool > Local attackers with write access to the mail spool directory can achieve arbitrary PHP code execution via insecure deserialization in TYPO3 CMS. - **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:** 13 Jan 2026 - **Updated:** 13 Jan 2026 - **Also known as:** GHSA-7vp9-x248-9vr9 ## What is CVE-2026-0859? CVE-2026-0859 is a medium-severity unsafe deserialization vulnerability in Typo3 Typo3, published on 13 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description TYPO3's mail‑file spool deserialization flaw lets local users with write access to the spool directory craft a malicious file that is deserialized during the mailer:spool:send command, enabling arbitrary PHP code execution on the web server. This issue affects TYPO3 CMS versions 10.0.0-10.4.54, 11.0.0-11.5.48, 12.0.0-12.4.40, 13.0.0-13.4.22 and 14.0.0-14.0.1. Weakness: CWE-502 (Deserialization of Untrusted Data) ## Which versions are affected by CVE-2026-0859? 10 open source packages ship an affected version, including typo3/cms-core. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `typo3/cms-core` | Packagist | From 10.0.0 | 10.4.55 | | `typo3/cms-core` | Packagist | From 10.0.0 | 10.4.55 | | `typo3/cms-core` | Packagist | From 11.0.0 | 11.5.49 | | `typo3/cms-core` | Packagist | From 11.0.0 | 11.5.49 | | `typo3/cms-core` | Packagist | From 12.0.0 | 12.4.41 | | `typo3/cms-core` | Packagist | From 12.0.0 | 12.4.41 | | `typo3/cms-core` | Packagist | From 13.0.0 | 13.4.23 | | `typo3/cms-core` | Packagist | From 13.0.0 | 13.4.23 | | `typo3/cms-core` | Packagist | From 14.0.0 | 14.0.2 | | `typo3/cms-core` | Packagist | From 14.0.0 | 14.0.2 | Products: Typo3 Typo3. ## How do I fix CVE-2026-0859? Upgrade typo3/cms-core to a fixed version for your release line: 10.4.55, 11.5.49, 12.4.41 or 13.4.23. ## Is CVE-2026-0859 being exploited? There is no known exploitation of CVE-2026-0859 in the wild and no public exploit code. ## Other vulnerabilities in Typo3 Typo3 - [CVE-2009-0258](https://insights.sbomify.com/CVE-2009-0258/): Indexed Search Engine for TYPO3 Command Execution via Metacharacter Injection (critical 10.0) - [CVE-2011-3583](https://insights.sbomify.com/CVE-2011-3583/): Typo3 SQL injection due to faulty prepared statements (critical 9.8) - [CVE-2011-4628](https://insights.sbomify.com/CVE-2011-4628/): Typo3 Authentication Bypass (critical 9.8) - [CVE-2023-24814](https://insights.sbomify.com/CVE-2023-24814/): Persisted Cross-Site Scripting in Frontend Rendering in typo3 (high 8.8) - [CVE-2021-41113](https://insights.sbomify.com/CVE-2021-41113/): Cross-Site-Request-Forgery in Backend URI Handling in Typo3 (high 8.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-0859 and fix it if it is affected. What it is: CVE-2026-0859 is a medium-severity unsafe deserialization vulnerability in Typo3 Typo3, published on 13 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-2026-0859 in the wild and no public exploit code. Affected packages and fixed versions: - typo3/cms-core (Packagist): affected from 10.0.0; fixed in 10.4.55 - typo3/cms-core (Packagist): affected from 10.0.0; fixed in 10.4.55 - typo3/cms-core (Packagist): affected from 11.0.0; fixed in 11.5.49 - typo3/cms-core (Packagist): affected from 11.0.0; fixed in 11.5.49 - typo3/cms-core (Packagist): affected from 12.0.0; fixed in 12.4.41 - typo3/cms-core (Packagist): affected from 12.0.0; fixed in 12.4.41 - typo3/cms-core (Packagist): affected from 13.0.0; fixed in 13.4.23 - typo3/cms-core (Packagist): affected from 13.0.0; fixed in 13.4.23 - typo3/cms-core (Packagist): affected from 14.0.0; fixed in 14.0.2 - typo3/cms-core (Packagist): affected from 14.0.0; fixed in 14.0.2 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-2026-0859/ (Markdown: https://insights.sbomify.com/CVE-2026-0859/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-0859 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-0859 - OSV: https://osv.dev/vulnerability/CVE-2026-0859 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-0859/ Summaries are generated and may contain mistakes; the official description above is the record.