CVE-2026-0859 — TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Typo3 Typo3, TYPO3 TYPO3 CMS).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Typo3 | Typo3 | ≥ 10.0.0 and < 10.4.55≥ 11.0.0 and < 11.5.49≥ 12.0.0 and < 12.4.41≥ 13.0.0 and < 13.4.23≥ 14.0.0 and < 14.0.2 | Vulnerable | NIST National Vulnerability Database |
| TYPO3 | TYPO3 CMS | ≥ 10.0.0 and < 10.4.55≥ 11.0.0 and < 11.5.49≥ 12.0.0 and < 12.4.41≥ 13.0.0 and < 13.4.23≥ 14.0.0 and < 14.0.2 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.2 | CVSS 4.0 | Medium | — | — | f4fb688c-4412-4426-b4b8-421ecf27b14a via NIST National Vulnerability Database |
| 5.2 | CVSS 4.0 | Medium | — | — | TYPO3 via CVE Program (cve.org) e CISA ADP |
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.18%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Monitor serialized objects in requests and unexpected processes spawned by the runtime.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · typo3/typo3 cms
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
4 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-109162 TYPO3 CMS - Security Misconfiguration in Form Framework 2d
- Low CVE-2026-49738 TYPO3 CMS - Broken Access Control in File Abstraction Layer Jun 9, 2026
- Medium CVE-2026-47352 TYPO3 CMS - Broken Access Control in Backend API Jun 9, 2026
- Medium CVE-2026-49740 TYPO3 CMS - Insecure Deserialization in Core API Jun 9, 2026
- High CVE-2026-49742 TYPO3 CMS - Broken Access Control in Media Module Jun 9, 2026
- High CVE-2026-49741 TYPO3 CMS - Privilege Escalation & SQL Injection in Form Framework Jun 9, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-0859 is "TYPO3 CMS Allows Insecure Deserialization via Mailer File Spool", rated High. It affects Typo3 (Typo3); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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