CVE-2026-54283
Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-770 |
| Vendor | kludex |
| Product | starlette |
| Published | Jun 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Kludex / starlette
>= 0.4.1, < 1.3.1