Vulnerability in typo3/cms-backend (CVE-2026-6553)
Summary
Vulnerability in typo3/cms-backend (CVE-2026-6553). Confidential information can be exposed externally. Exploitable via SetupModuleController. Mitigation: upgrade to 14.3.0 or later.
Original description
The description as published by the source.
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 requiredUpdating 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
ucanduser_settingsfields of thebe_userstable. 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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-6553 has been found in typo3/cms-backend.
Attackers can target a specific entry point like SetupModuleController over the network to misuse the product.
Confidential information can be exposed externally.
What to do: upgrade typo3/cms-backend to 14.3.0 or later.
If unsure, ask your IT team or search "typo3/cms-backend CVE-2026-6553" on the vendor's site.
CVE-2026-6553 (typo3/cms-backend) — CWE-312
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: SetupModuleController / user_settings / be_users
Patched: 14.3.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-312) exists in typo3/cms-backend. Attackers reach the vulnerable code path via SetupModuleController without authentication.
Check the vendor advisory for the affected versions of typo3/cms-backend. Attack surface: SetupModuleController / user_settings / be_users.
Severity: ?. Confidential information can be exposed externally.
Update to 14.3.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'typo3/cms-backend' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'typo3/cms-backend' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
typo3/cms-backendを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade typo3/cms-backend to 14.3.0ステージング環境で 14.3.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web typo3.org
- web github.com