The Advanced Custom Fields (ACF) Free and Pro WordPress plugins 6.x before 6.1.0 and 5.x before 5.12.5 unserialize user controllable data, which could allow users with a role of Contributor and above to perform PHP Object Injection when a suitable gadget is present.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Advanced_custom_fields | Advancedcustomfields | 5.0.0 (including) | 5.12.5 (excluding) |
| Advanced_custom_fields | Advancedcustomfields | 6.0.0 (including) | 6.1.0 (excluding) |
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.