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Vulnerability details: VCID-d8d1-sat6-muhe
Vulnerability ID VCID-d8d1-sat6-muhe
Aliases CVE-2021-21359
GHSA-4p9g-qgx9-397p
Summary Denial of Service in Page Error Handling > ### Meta > * CVSS: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C` (5.5) > * CWE-405, CWE-674 > * Status: **DRAFT** ### Problem Requesting invalid or non-existing resources via HTTP triggers the page error handler which again could retrieve content to be shown as error message from another page. This leads to a scenario in which the application is calling itself recursively - amplifying the impact of the initial attack until the limits of the web server are exceeded. ### Solution Update to TYPO3 versions 9.5.25, 10.4.14, 11.1.1 that fix the problem described. ### Credits Thanks to Paul Keller, Mathias Bolt Lesniak and Kay Strobach who reported this issue and to TYPO3 framework merger Frank Nägler and to TYPO3 security team member Torben Hansen who fixed the issue. ### References * [TYPO3-CORE-SA-2021-005](https://typo3.org/security/advisory/typo3-core-sa-2021-005)
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-405 Asymmetric Resource Consumption (Amplification)
CWE-674 Uncontrolled Recursion
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
epss 0.003 https://api.first.org/data/v1/epss?cve=CVE-2021-21359
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-4p9g-qgx9-397p
cvssv3.1 5.9 https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21359.yaml
generic_textual MODERATE https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21359.yaml
cvssv3.1 5.9 https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21359.yaml
generic_textual MODERATE https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21359.yaml
cvssv3.1 5.9 https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
cvssv3.1_qr MODERATE https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
generic_textual MODERATE https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
cvssv3.1 5.9 https://nvd.nist.gov/vuln/detail/CVE-2021-21359
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-21359
cvssv3.1 5.9 https://packagist.org/packages/typo3/cms-core
generic_textual MODERATE https://packagist.org/packages/typo3/cms-core
cvssv3.1 5.9 https://typo3.org/security/advisory/typo3-core-sa-2021-005
generic_textual MODERATE https://typo3.org/security/advisory/typo3-core-sa-2021-005
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-21359
https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21359.yaml
https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21359.yaml
https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
https://nvd.nist.gov/vuln/detail/CVE-2021-21359
https://packagist.org/packages/typo3/cms-core
https://typo3.org/security/advisory/typo3-core-sa-2021-005
GHSA-4p9g-qgx9-397p https://github.com/advisories/GHSA-4p9g-qgx9-397p
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21359.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21359.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-4p9g-qgx9-397p
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://nvd.nist.gov/vuln/detail/CVE-2021-21359
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://packagist.org/packages/typo3/cms-core
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C Found at https://typo3.org/security/advisory/typo3-core-sa-2021-005
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.5328
EPSS Score 0.003
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T13:01:55.956398+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/03/GHSA-4p9g-qgx9-397p/GHSA-4p9g-qgx9-397p.json 38.0.0