CVE-2026-6553: Typo3/cms backend TYPO3 CMS Stores Cleartext Password Vulnerability

HIGH
Advisory Identifier: GHSA-xvv6-p4wf-mvx7
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CVSS 7.5
CWE-312
Published
Advisory Summary

CVE-2026-6553 is a HIGH (CVSS 7.5) typo3 cms stores cleartext password vulnerability (CWE-312: Cleartext Storage of Sensitive Information) affecting Typo3/cms backend libraries in the Packagist ecosystem. The issue involves typo3 cms stores cleartext password in user settings module. Remediation is available by upgrading affected packages to version 14.3.0.

CVE-2026-6553 at a Glance

CVE Identifier CVE-2026-6553
GHSA Identifier GHSA-xvv6-p4wf-mvx7
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-312: Cleartext Storage of Sensitive Information
Affected Product Typo3/cms backend
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-6553

To remediate this vulnerability, upgrade all affected Typo3/cms backend dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

typo3/cms-backend fixed: 14.3.0 
Upgrade typo3/cms-backend to 14.3.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for typo3/cms-backend

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-6553, inspect your project dependencies for Typo3/cms backend:

inspect dependencies for typo3/cms-backend

Analyze the terminal output to locate any version of Typo3/cms backend in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 14.3.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-312: Cleartext Storage of Sensitive Information, where the product stores sensitive information in cleartext within a resource that might be accessible to another control sphere. In Typo3/cms backend, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Problem The backend user settings module (`SetupModuleController`) incorrectly conflates entity data (like passwords or email address) with user-interface settings (like theme, display options) when persisting changes. As a result, passwords were stored in cleartext in the `uc` and `user_settings` fields of the `be_users` database table. The cleartext data was only persisted if users changed their credentials in the backend user settings module when the TYPO3 14.2.0 release was used (not in any other version). ### Solution Update to TYPO3 version 14.3.0 LTS which fixes the problem described. > [!IMPORTANT] > **Manual actions required** > > Updating to the patched release does not retroactively clean existing data. It is recommended to execute all User Settings upgrade wizards in the TYPO3 Install Tool, including the dedicated User Settings Scrubbing wizard, which sanitizes the incorrectly persisted cleartext values from the `uc` and `user_settings` fields of the `be_users` table. **Additionally, affected backend user accounts should be assigned new passwords.** > > _Admin Tools → Upgrade → Upgrade Wizard → User Settings Scrubbing_ ### Credits TYPO3 thanks Martin Clewing for reporting this issue, and TYPO3 core team members Oliver Hader, Stefan Bürk and Garvin Hicking for fixing it.

CVE-2026-6553 Affected Typo3/cms backend Versions

1 component(s)
Fixed Versions:
14.3.0
Product / Package Ecosystem Affected Versions Fixed Version
typo3/cms-backend
 Packagist
≥ 14.2.0
< 14.3.0
All 1 versions
14.2.0
14.3.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/TYPO3/typo3/security/advisories/GHSA-xvv6-p4wf-mvx7
NVD — CVE-2026-6553 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-6553
Security Fix Commit FIX COMMIT
https://github.com/TYPO3/typo3/commit/9a6e913f70767f63b322ae3e2d2f4e302624c291
Typo3/cms backend Source Repository REPOSITORY
https://github.com/TYPO3/typo3
Typo3/cms backend Security Information SECURITY
https://typo3.org/security/advisory/typo3-core-sa-2026-005

Frequently Asked Questions

What is CVE-2026-6553?
CVE-2026-6553 is a security vulnerability in Typo3/cms backend involving TYPO3 CMS Stores Cleartext Password in User Settings Module under CWE-312: Cleartext Storage of Sensitive Information.
Which Typo3/cms backend versions are affected?
Affected versions include releases prior to 14.3.0 across affected packages: typo3/cms-backend.
What version fixes CVE-2026-6553?
Upgrading to 14.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is typo3/cms-backend affected?
Yes, typo3/cms-backend is affected in releases prior to 14.3.0. Upgrade your dependency to 14.3.0 or later.
What is the CVSS score of CVE-2026-6553?
CVE-2026-6553 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-6553?
CVE-2026-6553 is classified under CWE-312: Cleartext Storage of Sensitive Information (The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere.).
How can I check Packagist dependencies for CVE-2026-6553?
Run the dependency tree command: 'inspect dependencies for typo3/cms-backend'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xvv6-p4wf-mvx7",
  "modified" : "2026-05-08T15:20:40Z",
  "published" : "2026-04-24T16:39:15Z",
  "aliases" : [ "CVE-2026-6553" ],
  "summary" : "TYPO3 CMS Stores Cleartext Password in User Settings Module",
  "details" : "### Problem\nThe backend user settings module (`SetupModuleController`) incorrectly conflates entity data (like passwords or email address) with user-interface settings (like theme, display options) when persisting changes. As a result, passwords were stored in cleartext in the `uc` and `user_settings` fields of the `be_users` database table.\n\nThe cleartext data was only persisted if users changed their credentials in the backend user settings module when the TYPO3 14.2.0 release was used (not in any other version).\n\n### Solution\nUpdate to TYPO3 version 14.3.0 LTS which fixes the problem described.\n\n> [!IMPORTANT]\n> **Manual actions required**\n> \n> Updating to the patched release does not retroactively clean existing data. It is recommended to execute all User Settings upgrade wizards in the TYPO3 Install Tool, including the dedicated User Settings Scrubbing wizard, which sanitizes the incorrectly persisted cleartext values from the `uc` and `user_settings` fields of the `be_users` table. **Additionally, affected backend user accounts should be assigned new passwords.**\n> \n> _Admin Tools → Upgrade → Upgrade Wizard → User Settings Scrubbing_\n\n### Credits\nTYPO3 thanks Martin Clewing for reporting this issue, and TYPO3 core team members Oliver Hader, Stefan Bürk and Garvin Hicking for fixing it.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-backend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "14.2.0"
      }, {
        "fixed" : "14.3.0"
      } ]
    } ],
    "versions" : [ "14.2.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/typo3/security/advisories/GHSA-xvv6-p4wf-mvx7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-6553"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/typo3/commit/9a6e913f70767f63b322ae3e2d2f4e302624c291"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/TYPO3/typo3"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-core-sa-2026-005"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-312" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-24T16:39:15Z",
    "nvd_published_at" : "2026-04-21T10:16:31Z"
  }
}