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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Kludex starlette affected
Version Status Constraints
>= 0.4.1, < 1.3.1 affected —

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Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-82w8-qh3p-5jfq Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/Kludex/starlette/security/advisories/GHSA-82w8-qh3p-5jfq cve-icon
History

Mon, 22 Jun 2026 17:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-22T16:46:16.706Z

Reserved: 2026-06-12T17:46:37.292Z

Link: CVE-2026-54283

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses