TYPO3CMS
CVE-2020-11066
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.17 and greater than or equal to 10.0.0 and less than 10.4.2, calling unserialize() on malicious user-submitted content can lead to modification of dynamically-determined object attributes and result in triggering deletion of an arbitrary directory in the file system, if it is writable for the web server. It can also trigger message submission via email using the identity of the web site (mail relay). Another insecure deserialization vulnerability is required to actually exploit mentioned aspects. This has been fixed in 9.5.17 and 10.4.2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceInsecure deserialization vulnerability in TYPO3 CMS where calling unserialize() on malicious user-submitted content allows modification of dynamically-determined object attributes, enabling arbitrary directory deletion (if writable by web server) and email relay abuse. Another insecure deserialization vulnerability is required for full exploitation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
TYPO3CMS
>= 9.0.0, < 9.5.17>= 10.0.0, < 10.4.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed TYPO3 versionLog into the TYPO3 backend as administrator and navigate to Admin Tools > About > Version Information, or check the file typo3/sysext/core/ClassLoader.php for the version constantAffected if The version is 9.0.0 through 9.5.16, or 10.0.0 through 10.4.1 (these fall within the affected ranges of >= 9.0.0, < 9.5.17 and >= 10.0.0, < 10.4.2)
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Verify PHP unserialize() usage in custom extensionsSearch the codebase for calls to unserialize() on user-submitted data, typically found in ext_localconf.php or custom controller filesAffected if Custom or third-party extensions call unserialize() on data derived from $_GET, $_POST, or database fields without a permitted_class argument
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Check for additional insecure deserialization entry pointsAudit all extensions for __destruct or __wakeup magic methods that could be chained with the primary vulnerabilityAffected if Multiple unserialize() calls exist in the application without strict allowed_class filtering
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Assess web server file system permissionsReview the file system permissions of the web server process user - check write access to typo3temp/, fileadmin/, and other writable directoriesAffected if The web server user has write permissions to directories that could be targeted for arbitrary deletion or modification
You are affected if your TYPO3 installation version is 9.0.0 through 9.5.16 or 10.0.0 through 10.4.1 AND your system processes untrusted input through unserialize() without class filtering.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped9.5.1710.4.2
Upgrade TYPO3 CMS to version 9.5.17 or 10.4.2 or later to patch the insecure deserialization vulnerability. Also ensure the web server process has minimal file system permissions to limit impact of any deserialization exploitation.
Upgrade to TYPO3 9.5.17 or 10.4.2 (or latest stable in respective branch)
- Upgrade TYPO3 CMS from any version >= 9.0.0 and < 9.5.17 to version 9.5.17 or later within the 9.5.x branch
- OR upgrade TYPO3 CMS from any version >= 10.0.0 and < 10.4.2 to version 10.4.2 or later within the 10.4.x branch
- After upgrade, clear all caches via Install Tool or CLI: ./typo3cms cache:flush
- Verify the upgrade was successful and the TYPO3 admin panel is accessible
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in TYPO3
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-11066 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-11066 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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