wire-webapp is the web application for the open-source messaging service Wire. A bug fix caused a regression causing an issue with function to delete local data. Instructing the client to delete its local database on user logout does not result in deletion. This is the case for both temporary clients (marking the device as a public computer on login) and regular clients instructing the deletion of all personal information and conversations upon logout. Access to the machine is required to access the data. If encryption-at-rest is used, cryptographic material cant be exported. The underlying issue has been fixed with wire-webapp version 2025-05-14-production.0. In order to mitigate potential impact, the database must be manually deleted on devices where the option This is a public computer was used prior to log in or a log out with the request to delete local data with the affected versions has happened before.
The product releases a resource such as memory or a file so that it can be made available for reuse, but it does not clear or “zeroize” the information contained in the resource before the product performs a critical state transition or makes the resource available for reuse by other entities.
When resources are released, they can be made available for reuse. For example, after memory is de-allocated, an operating system may make the memory available to another process, or disk space may be reallocated when a file is deleted. As removing information requires time and additional resources, operating systems do not usually clear the previously written information. Even when the resource is reused by the same process, this weakness can arise when new data is not as large as the old data, which leaves portions of the old data still available. Equivalent errors can occur in other situations where the length of data is variable but the associated data structure is not. If memory is not cleared after use, the information may be read by less trustworthy parties when the memory is reallocated. This weakness can apply in hardware, such as when a device or system switches between power, sleep, or debug states during normal operation, or when execution changes to different users or privilege levels.