Vulnerability in typo3/cms-core (CVE-2021-41114)

Summary

Vulnerability in typo3/cms-core (CVE-2021-41114). Risk of unauthorized operations or information disclosure. Exploitable via Host header. Mitigation: upgrade to 11.5.0 or later.

Original description

The description as published by the source.

Problem

It has been discovered that TYPO3 CMS is susceptible to host spoofing due to improper validation of the HTTP Host header. TYPO3 uses the HTTP Host header, for example, to generate absolute URLs during the frontend rendering process. Since the host header itself is provided by the client, it can be forged to any value, even in a name-based virtual hosts environment.

This vulnerability is the same as described in TYPO3-CORE-SA-2014-001 (CVE-2014-3941). A regression, introduced during TYPO3 v11 development, led to this situation. The already existing setting $GLOBALS['TYPO3_CONF_VARS']['SYS']['trustedHostsPattern'] (used as an effective mitigation strategy in previous TYPO3 versions) was not evaluated anymore, and reintroduced the vulnerability.

Solution

Update your instance to TYPO3 version 11.5.0 which addresses the problem described.

Credits

Thanks to TYPO3 framework merger Benjamin Franzke who reported and fixed the issue.

References

TYPO3-CORE-SA-2021-015
CVE-2014-3941 reintroduced in TYPO3 v11.0.0

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

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-2021-41114 has been found in typo3/cms-core.
Attackers can target a specific entry point like Host header over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade typo3/cms-core to 11.5.0 or later.
If unsure, ask your IT team or search "typo3/cms-core CVE-2021-41114" on the vendor's site.

CVE-2021-41114 (typo3/cms-core) — CWE-20
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Host header
Patched: 11.5.0 — 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.

❓ What is the problem

A vulnerability (CWE-20) exists in typo3/cms-core. Attackers reach the vulnerable code path via Host header without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of typo3/cms-core. Attack surface: Host header.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 11.5.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'typo3/cms-core' . 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

1
Identify exposure identify
```
grep -r 'typo3/cms-core' . | 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-core を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade typo3/cms-core to 11.5.0
```
ステージング環境で 11.5.0 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。
3
Post-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

Packagist typo3/cms-core

[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0"},{"fixed":"11.5.0"}]}]

Packagist typo3/cms

[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0"},{"fixed":"11.5.0"}]}]

References

advisory nvd.nist.gov
advisory nvd.nist.gov
package github.com
web github.com
web github.com
web github.com
web github.com
web typo3.org