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TYPO3CMS

CVE-2021-21339

HIGH · 7.5 CVSS v3.1 Published 2021-03-23
Fix available
A fix is available. Upgrade to 6.2.57 / 7.6.51 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
TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 user session identifiers were stored in cleartext - without processing of additional cryptographic hashing algorithms. This vulnerability cannot be exploited directly and occurs in combination with a chained attack - like for instance SQL injection in any other component of the system. This is fixed in versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.

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

TYPO3 CMS stores user session identifiers in cleartext without cryptographic hashing. This vulnerability is not directly exploitable but requires a chained attack (such as SQL injection) to access the cleartext session data and hijack user sessions.

MitigationUpgrade to TYPO3 versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, or 11.1.1 or later. Additionally, address any SQL injection vulnerabilities and implement defense-in-depth controls to protect session data.

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
Affected:>= 6.2.0, < 6.2.57>= 7.0.0, < 7.6.51>= 8.0.0, < 8.7.40>= 9.0.0, < 9.5.25>= 10.0.0, < 10.4.14>= 11.0.0, < 11.1.1

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 installed TYPO3 version
    Check the file typo3/sysext/core/Classes/Utility/GeneralUtility.php or the TYPO3 admin panel (Help > About) for the exact version number
    Affected if The installed version falls within any of these ranges: 6.2.0-6.2.56, 7.0.0-7.6.50, 8.0.0-8.7.39, 9.0.0-9.5.24, 10.0.0-10.4.13, or 11.0.0-11.1.0
  2. Locate session storage configuration
    Inspect the TYPO3 configuration file typo3conf/LocalConfiguration.php or typo3conf/AdditionalConfiguration.php for 'BE' or 'FE' session settings, specifically the 'session' section
    Affected if Session storage is configured to use database-based sessions (not file-based) and no hashing algorithm is specified
  3. Inspect database session table
    Query the database table 'be_sessions' (backend) or 'fe_sessions' (frontend) for stored session data, for example: SELECT ses_id, ses_data FROM be_sessions LIMIT 5;
    Affected if The 'ses_id' column contains plain session identifiers without cryptographic hashing (compare against expected hashed formats)
  4. Check for SQL injection vulnerabilities
    Review custom TYPO3 extensions for unsanitized database queries, or use TYPO3's security scanning tools to audit extension code
    Affected if SQL injection vulnerabilities exist that could be chained with this session exposure flaw

You are affected if your TYPO3 version is within any of the listed vulnerable ranges and your session data is stored in cleartext in the database.

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.

From vendor data
Upgrade available Upgrade to 6.2.57 / 7.6.51 / 8.7.40 or later
Fixed in 6.2.577.6.518.7.40
Interim mitigation

Upgrade to TYPO3 versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, or 11.1.1 or later. Additionally, address any SQL injection vulnerabilities and implement defense-in-depth controls to protect session data.

Fix this in TYPO3 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.

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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-2021-21339 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