dbcve.org
RoutesTYPO3 extension · Routes Project

CVE-2021-36793

HIGH · 7.5 CVSS v3.1 Published 2021-08-13
Fix available
A fix is available. Upgrade to 2.1.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
The routes (aka Extbase Yaml Routes) extension before 2.1.1 for TYPO3, when CsrfTokenViewHelper is used, allows Sensitive Information Disclosure because a session identifier is unsafely present in HTML output.

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

The Extbase Yaml Routes extension for TYPO3 before version 2.1.1 exposes session identifiers in HTML output when the CsrfTokenViewHelper is used, allowing sensitive information disclosure that could enable session hijacking.

MitigationUpgrade the routes (Extbase Yaml Routes) extension to version 2.1.1 or later to remove the unsafe session identifier exposure in HTML output.

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
RoutesTYPO3 extension
Affected:< 2.1.1

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

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

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. Identify if Routes extension is installed
    In TYPO3 backend, go to Extension Manager or use CLI (typo3cms extension:list) to check if the 'routes' or 'extbase_yaml_routes' extension is installed.
    Affected if The routes extension is not present in the installation.
  2. Check installed Routes extension version
    In TYPO3 backend, view extension details in Extension Manager to see the installed version number, or check the ext_emconf.php file in the extension directory (typically in typo3conf/ext/routes/).
    Affected if Installed version is less than 2.1.1.
  3. Verify CsrfTokenViewHelper usage in templates
    Search project templates (in fileadmin/ or typo3conf/ext/) for usage of CsrfTokenViewHelper, typically seen as <f:security.csrfToken /> or similar ViewHelper tags in Fluid templates.
    Affected if CsrfTokenViewHelper is used in any template files.
  4. Inspect HTML output for session identifiers
    View rendered HTML pages (view source) where CsrfTokenViewHelper is used, and search for session-related parameters or tokens in the output.
    Affected if Session identifiers or tokens appear visibly in the rendered HTML source.

User is affected if Routes extension version is below 2.1.1 AND CsrfTokenViewHelper is used in templates, resulting in visible session identifiers in HTML output.

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 2.1.1 or later
Fixed in 2.1.1
Interim mitigation

Upgrade the routes (Extbase Yaml Routes) extension to version 2.1.1 or later to remove the unsafe session identifier exposure in HTML output.

Recommended fix Moderate confidence

routes extension version 2.1.1

  1. Identify all TYPO3 installations using the 'routes' (Extbase Yaml Routes) extension with versions prior to 2.1.1
  2. Backup your TYPO3 database and extension files before making changes
  3. Upgrade the routes extension to version 2.1.1 or later using the TYPO3 Extension Manager or Composer
  4. Clear all TYPO3 caches after the upgrade (via Install Tool > Clear caches)
  5. Verify that CsrfTokenViewHelper no longer exposes session identifiers in HTML output by inspecting page source
Caveat Test the upgrade in a staging environment before deploying to production to ensure compatibility with your TYPO3 version and other extensions

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

Fix this in Routes Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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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-2021-36793 in production — separate from our analysis above.

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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