CVE-2021-21359

Denial of Service in Page Error Handling

HIGH
7.5
CVSS Score
Published: March 23, 2021 at 01:55 AM UTC
Updated: June 17, 2026 at 03:35 AM UTC
1 product affected across 1 vendorTYPO3

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Severity
HIGH7.5
Exploit prediction
EPSS 2%

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 9.5.25, 10.4.14, 11.1.1 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. This is fixed in versions 9.5.25, 10.4.14, 11.1.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

95%
v ≤ 10.4.13v ≤ 11.1.0v ≤ 9.5.2410.0.0 ≤ v < 10.4.1411.0.0 ≤ v < 11.1.19.0.0 ≤ v < 9.5.25
Affected range stops below 10.4.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 11.1.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.5.25, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-405CWE-674

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