CVE-2020-15099: Exposure of Sensitive Information to an Unauthorized Actor in TYPO3 CMS

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-07-29 · updated 2026-06-17
Weakness: CWE-20

Description

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, in a case where an attacker manages to generate a valid cryptographic message authentication code (HMAC-SHA1) - either by using a different existing vulnerability or in case the internal encryptionKey was exposed - it is possible to retrieve arbitrary files of a TYPO3 installation. This includes the possibility to fetch typo3conf/LocalConfiguration.php, which again contains the encryptionKey as well as credentials of the database management system being used. In case a database server is directly accessible either via internet or in a shared hosting network, this allows the ability to completely retrieve, manipulate or delete database contents. This includes creating an administration user account - which can be used to trigger remote code execution by injecting custom extensions. This has been patched in versions 9.5.20 and 10.4.6.

Affected products

typo3: from 9.0.0 before 9.5.20; from 10.0.0 before 10.4.6 — fixed in 10.4.6, 9.5.20

How to fix

Upgrade to a fixed version: typo3 10.4.6, 9.5.20. Check the vendor advisory for mitigations.

References

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