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ContaoApplication

CVE-2021-37627

HIGH · 7.2 CVSS v3.1 Published 2021-08-11
Fix available
A fix is available. Upgrade to 4.4.56 / 4.9.18 or later.
See remediation →
78/100
Remediation priority · High
Remotely reachable Zero-click

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 · unedited
Contao is an open source CMS that allows creation of websites and scalable web applications. In affected versions it is possible to gain privileged rights in the Contao back end. Installations are only affected if they have untrusted back end users who have access to the form generator. All users are advised to update to Contao 4.4.56, 4.9.18 or 4.11.7. As a workaround users may disable the form generator or disable the login for untrusted back end users.

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 confidence

Contao CMS contains a privilege escalation vulnerability allowing untrusted back end users with access to the form generator to gain elevated privileges in the back end. The vulnerability stems from insufficient access controls within the form generator functionality.

MitigationUpdate Contao to version 4.4.56, 4.9.18, or 4.11.7. Alternatively, disable the form generator or restrict login access for untrusted back end users as a workaround.

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
ContaoApplication
Affected:>= 4.4.0, < 4.4.56>= 4.9.0, < 4.9.18>= 4.11.0, < 4.11.7= 4.0.0= 4.1.0= 4.2.0= 4.3.0= 4.5.0= 4.6.0= 4.7.0= 4.8.0= 4.10.0

CVSS 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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine Contao version
    Locate the core version file or check the installed package version via composer or system info page. In Contao 4.x, the version is typically visible in the system/initialization or can be queried via the management console.
    Affected if Installed version matches one of the affected ranges: >= 4.4.0 and < 4.4.56, or >= 4.9.0 and < 4.9.18, or >= 4.11.0 and < 4.11.7, or exactly 4.0.0, 4.1.0, 4.2.0, 4.3.0, 4.5.0, 4.6.0, 4.7.0, 4.8.0, or 4.10.0
  2. Verify form generator is accessible
    Check if the form generator module is enabled in the Contao back end by reviewing the user/group permissions for access to the form generator functionality. Navigate to the access rights section for user groups.
    Affected if The form generator extension is installed and active, and the Contao installation is on an affected version
  3. Identify untrusted backend users with form generator access
    Review all backend user accounts and their assigned groups. Check the group permissions to determine which users have access to the form generator feature. Look for users who should NOT have elevated privileges but have form generator permissions.
    Affected if There are backend users with form generator access who are not fully trusted or who should not have elevated privileges

You are affected if your Contao version falls within the vulnerable ranges AND the form generator is enabled AND untrusted users have access to it.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 4.4.56 / 4.9.18 / 4.11.7 or later
Fixed in 4.4.564.9.184.11.7
Interim mitigation

Update Contao to version 4.4.56, 4.9.18, or 4.11.7. Alternatively, disable the form generator or restrict login access for untrusted back end users as a workaround.

Recommended fix High confidence

Upgrade to Contao 4.4.56, 4.9.18, or 4.11.7 (matching your current branch)

  1. Backup your Contao installation and database before updating
  2. Update Contao using Composer: `composer require contao/core-bundle:4.4.56` (or 4.9.18 or 4.11.7 depending on your current branch)
  3. Clear the application cache after updating (delete var/cache/prod/* or run contao:cache-clear command)
  4. Verify the update was successful by checking the Contao version in the back end
  5. Ensure all untrusted back end users no longer have access to the form generator module
Caveat Minor version updates within the same branch (e.g., 4.4.x) should be safe; however, review release notes for any configuration or feature changes before upgrading across branches

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Contao Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-37627 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data