TYPO3 CMS: Deserialization of Untrusted Data
CVE-2026-0859 is a high-severity deserialization of untrusted data vulnerability in TYPO3 CMS from TYPO3, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 10.4.55, 11.5.49, 12.4.41 as the first without the flaw, so updating TYPO3 CMS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.18% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update TYPO3 CMS to 10.4.55 or 11.5.49 or 12.4.41 or 13.4.23, whichever matches your release line, or a later version.
- Update Typo3 to 10.4.55 or 11.5.49 or 12.4.41 or 13.4.23, whichever matches your release line, or a later version.
- Read the advisory on typo3.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| TYPO3 | TYPO3 CMS | 10.0.0 up to, but not including, 10.4.55; 11.0.0 up to, but not including, 11.5.49; 12.0.0 up to, but not including, 12.4.41; 13.0.0 up to, but not including, 13.4.23; 14.0.0 up to, but not including, 14.0.2 | 10.4.55, 11.5.49, 12.4.41, 13.4.23, 14.0.2 |
| TYPO3 | Typo3 | 10.0.0 up to, but not including, 10.4.55; 11.0.0 up to, but not including, 11.5.49; 12.0.0 up to, but not including, 12.4.41; 13.0.0 up to, but not including, 13.4.23; 14.0.0 up to, but not including, 14.0.2 | 10.4.55, 11.5.49, 12.4.41, 13.4.23, 14.0.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.2 | Medium | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in TYPO3 CMS
- 7.5 High severity
- 7.3 High severity
- 7.1 High severity
- 8.7 High severity
- 7.6 High severity
- 7.2 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
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