Kludex starlette up to 1.3.0 request.form allocation of resources

Summaryinfo

A vulnerability marked as problematic has been reported in Kludex starlette up to 1.3.0. This issue affects the function request.form. The manipulation leads to allocation of resources. This vulnerability is documented as CVE-2026-54283. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Kludex starlette up to 1.3.0. It has been rated as problematic. This issue affects the function request.form. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to 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. Impacted is availability. The summary by CVE is:

Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-54283 since 06/12/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 1.3.1 eliminates this vulnerability.

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Productinfo

Vendor

• Kludex

Name

• starlette

Version

• 1.0
• 1.1
• 1.2
• 1.3.0

Website

• Product: https://github.com/Kludex/starlette/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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