CVE-2021-46364

A vulnerability in the Snake YAML parser of Magnolia CMS v6.2.3 and below allows attackers to execute arbitrary code via a crafted YAML file.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://docs.magnolia-cms.com/product-docs/6.2/Releases/Release-notes-for-Magnolia-CMS-6.2.4.html#_security_advisory
• https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2021-46364-YAML%20Deserialization-Magnolia%20CMS
• https://docs.magnolia-cms.com/product-docs/6.2/Releases/Release-notes-for-Magnolia-CMS-6.2.4.html#_security_advisory
• https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2021-46364-YAML%20Deserialization-Magnolia%20CMS