Pallets Werkzeug up to 2.2.2 Form Data Multipart Parser allocation of resources

Summaryinfo

A vulnerability was found in Pallets Werkzeug up to 2.2.2. It has been classified as problematic. Affected by this issue is some unknown functionality of the component Form Data Multipart Parser. Performing a manipulation results in allocation of resources. This vulnerability is cataloged as CVE-2023-25577. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Pallets Werkzeug up to 2.2.2. This affects an unknown code block of the component Form Data Multipart Parser. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE is:

Werkzeug is a comprehensive WSGI web application library. Prior to version 2.2.3, Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory as Python data. If a request can be made to an endpoint that accesses `request.data`, `request.form`, `request.files`, or `request.get_data(parse_form_data=False)`, it can cause unexpectedly high resource usage. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. The amount of RAM required can trigger an out of memory kill of the process. Unlimited file parts can use up memory and file handles. If many concurrent requests are sent continuously, this can exhaust or kill all available workers. Version 2.2.3 contains a patch for this issue.

The weakness was shared 02/15/2023 as GHSA-xg9f-g7g7-2323. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2023-25577 since 02/07/2023. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 276278 (TencentOS Server 4: python-werkzeug (TSSA-2025:0049)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.2.3 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 517cac5a804e8c4dc4ed038bb20dacd038e7a9f1 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.

The vulnerability is also documented in the vulnerability database at Tenable (276278). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• Pallets

Name

• Werkzeug

Version

• 2.2.0
• 2.2.1
• 2.2.2

License

• open-source

Website

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

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Be aware that VulDB is the high quality source for vulnerability data.

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