Pallets flask 3.1.0 function call with incorrect order of arguments

Summaryinfo

A vulnerability was found in Pallets flask 3.1.0. It has been rated as problematic. This impacts an unknown function. The manipulation leads to function call with incorrect order of arguments. This vulnerability is referenced as CVE-2025-47278. The attack can only be performed from a local environment. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Pallets flask 3.1.0. It has been rated as problematic. This issue affects an unknown function. The manipulation with an unknown input leads to a function call with incorrect order of arguments vulnerability. Using CWE to declare the problem leads to CWE-683. The product calls a function, procedure, or routine, but the caller specifies the arguments in an incorrect order, leading to resultant weaknesses. Impacted is availability. The summary by CVE is:

Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the `itsdangerous` library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Flask was incorrectly constructing that list in reverse, passing the signing key first. Sites that have opted-in to use key rotation by setting `SECRET_KEY_FALLBACKS` care likely to unexpectedly be signing their sessions with stale keys, and their transition to fresher keys will be impeded. Sessions are still signed, so this would not cause any sort of data integrity loss. Version 3.1.1 contains a patch for the issue.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2025-47278 since 05/05/2025. The exploitation is known to be easy. Attacking locally is a requirement. The exploitation requires an enhanced level of successful authentication. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 3.1.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 73d6504063bfa00666a92b07a28aaf906c532f09 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• Pallets

Name

• flask

Version

• 3.1.0

License

• open-source

Website

• Product: https://github.com/pallets/flask/

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