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CVE-2021-41114

HTTP Host Header Injection in Request Handling in Typo3

4.8 MediumFix available

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
Low

Exploit likelihood

1.22%Up 0.3 points since Oct 6, 2021
90%50%10%1%

What each source reports

CVE List Score used 4.8

HTTP Host Header Injection in Request Handling in Typo3

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Record
CVE-2021-41114
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness
CWE-20, CWE-644
Updated
2026-11-02
EUVDEUVD-2021-2219 4.8

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Record
EUVD-2021-2219
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Updated
2026-11-03
GitHub AdvisoriesGHSA-m2jh-fxw4-gphm 4.8

HTTP Host Header Injection

Meta

  • CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C (3.5)

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

Record
GHSA-m2jh-fxw4-gphm
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness
CWE-20, CWE-644
Updated
2026-11-02
NVD 4.8

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Record
CVE-2021-41114
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-20, CWE-644
Updated
2026-11-02
OSV 5.3

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Record
CVE-2021-41114
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated
2026-11-02
OSVGHSA-m2jh-fxw4-gphm 4.8

HTTP Host Header Injection

Meta

  • CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C (3.5)

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

Record
GHSA-m2jh-fxw4-gphm
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness
CWE-20, CWE-644
Updated
2026-11-02
OSVBIT-typo3-2021-41114 No score

TYPO3 is an open source PHP based web content management system released under the GNU GPL. 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.

Record
BIT-typo3-2021-41114
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
typo3/cms-core
Packagist
 11.0.0 up to 11.5.0
11.5.0
typo3/cms
Packagist
 11.0.0 up to 11.5.0
11.5.0
typo3
Bitnami
 11.0.0 up to 11.5.0
11.5.0
typo3/cms-core
Packagist
 11.0.0 up to 11.5.0, plus listed versions
v11.0.0v11.1.0v11.1.1v11.2.0v11.3.0
Show 4 moreShow less
v11.3.1v11.3.2v11.3.3v11.4.0
11.5.0
typo3/cms
Packagist
 11.0.0 up to 11.5.0, plus listed versions
v11.0.0v11.1.0v11.1.1v11.2.0v11.3.0
Show 4 moreShow less
v11.3.1v11.3.2v11.3.3v11.4.0
11.5.0

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-41114 is a medium vulnerability (CVSS 4.8) in Typo3, published October 5, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.22%, the 68th percentile. Fixed in typo3/cms-core 11.5.0.

References

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