CVE-2020-15098: TYPO3 CMS Arbitrary Checksum Generation Vulnerability

typo3 Updated 02 Oct 2025

Summary

06/03/2024
Yes i
High
Not published

CVE-2020-15098: In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, it has been discovered that an internal verification mechanism can be used to generate arbitrary... Affects typo3 across 2 version ranges.

>= 9.0.0, < 9.5.20 >= 10.0.0, < 10.4.6

Fixed in 9.5.20 or 10.4.6, depending on the release line you run. How to fix ↓

Also tracked for

The same CVE-2020-15098 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.

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Background

TYPO3 CMS is an open-source content management system that allows users to create and manage websites. It provides a wide range of features and functionalities for website development, including a backend user session for authenticated access. However, versions greater than or equal to 9.0.0 and less than 9.5.20, as well as versions greater than or equal to 10.0.0 and less than 10.4.6, are vulnerable to an arbitrary checksum generation flaw.

Vulnerability Detail

The vulnerability in TYPO3 CMS allows an attacker to generate arbitrary checksums using an internal verification mechanism. This enables the injection of arbitrary data with a valid cryptographic message authentication code (HMAC-SHA1). The impact of this vulnerability can lead to various attack chains, including potential privilege escalation, insecure deserialization, and remote code execution. It is important to note that exploiting this vulnerability requires a valid backend user session (authenticated). The severity of this vulnerability is considered high due to the mentioned attack chains and the potential consequences.

How To Fix

Fixed versions by release line

The minimum fixed version depends on the release line you run.

  • >= 9.0.0, < 9.5.20 9.5.20
  • >= 10.0.0, < 10.4.6 10.4.6

Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →

Workaround

There is no known workaround for this vulnerability. It is essential to apply the provided patches or update to the fixed versions to ensure the security of the TYPO3 CMS installation.

Conclusion

The arbitrary checksum generation vulnerability in TYPO3 CMS poses a significant risk, potentially leading to privilege escalation, insecure deserialization, and remote code execution. It is crucial to update the CMS to the patched versions or apply the provided fixes to ensure the security of the installation. For further support on vulnerability remediation, contact DevNack.com.

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FAQ

TYPO3 CMS is an open-source content management system used for website development and management.

Versions greater than or equal to 9.0.0 and less than 9.5.20, as well as versions greater than or equal to 10.0.0 and less than 10.4.6, are affected.

The vulnerability can lead to various attack chains, including potential privilege escalation, insecure deserialization, and remote code execution.

Yes, exploiting this vulnerability requires a valid backend user session (authenticated).

To fix this vulnerability, update TYPO3 CMS to version 9.5.20 or 10.4.6, depending on the installed version.

Related vulnerabilities

Recent vulnerabilities recorded for typo3.

How To Fix

Fixed versions by release line

The minimum fixed version depends on the release line you run.

  • >= 9.0.0, < 9.5.20 9.5.20
  • >= 10.0.0, < 10.4.6 10.4.6

Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →

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