MediumGHSA-4p9g-qgx9-397pBIT-typo3-2021-21359CVE-2021-21359

Denial of Service in Page Error Handling

Published 23 Mar 2021 · Updated 8 Jul 2026

Affected packages

typo3/cms-coreComposer
Affected
>=10.0.0 <10.4.14
Fixed in
10.4.14
Update to the fixed version for your release line, for example:composer require typo3/cms-core:^10.4.14
typo3/cms-coreComposer
Affected
>=11.0.0 <11.1.1
Fixed in
11.1.1
Update to the fixed version for your release line, for example:composer require typo3/cms-core:^11.1.1
typo3/cms-coreComposer
Affected
>=9.0.0 <9.5.25
Fixed in
9.5.25
Update to the fixed version for your release line, for example:composer require typo3/cms-core:^9.5.25
typo3/cmsComposer
Affected
>=10.0.0 <10.4.14
Fixed in
10.4.14
Update to the fixed version for your release line, for example:composer require typo3/cms:^10.4.14
typo3/cmsComposer
Affected
>=11.0.0 <11.1.1
Fixed in
11.1.1
Update to the fixed version for your release line, for example:composer require typo3/cms:^11.1.1
typo3/cmsComposer
Affected
>=9.0.0 <9.5.25
Fixed in
9.5.25
Update to the fixed version for your release line, for example:composer require typo3/cms:^9.5.25

Details

> ### 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

Is GHSA-4p9g-qgx9-397p in any of your client repos?

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References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.