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TYPO3 CMS Possible Insecure Deserialization in Extbase Request Handling

High severity GitHub Reviewed Published Jun 7, 2024 to the GitHub Advisory Database • Updated Jun 7, 2024

Package

composer typo3/cms (Composer)

Affected versions

>= 8.0.0, < 8.7.30
>= 9.0.0, < 9.5.12

Patched versions

8.7.30
9.5.12

Description

It has been discovered that request handling in Extbase can be vulnerable to insecure deserialization. User submitted payload has to be signed with a corresponding HMAC-SHA1 using the sensitive TYPO3 encryptionKey as secret - invalid or unsigned payload is not deserialized.

However, since sensitive information could have been leaked by accident (e.g. in repositories or in commonly known and unprotected backup files), there is the possibility that attackers know the private encryptionKey and are able to calculate the required HMAC-SHA1 to allow a malicious payload to be deserialized.

Requirements for successfully exploiting this vulnerability (all of the following):

  • rendering at least one Extbase plugin in the frontend
  • encryptionKey has been leaked (from LocalConfiguration.php or corresponding .env file)

References

Published to the GitHub Advisory Database Jun 7, 2024
Reviewed Jun 7, 2024
Last updated Jun 7, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

No CWEs

CVE ID

No known CVE

GHSA ID

GHSA-hh95-5xm5-v8v7

Source code

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