CVE-2025-62727

Starlette is a lightweight ASGI framework/toolkit. Starting in version 0.39.0 and prior to version 0.49.1 , an unauthenticated attacker can send a crafted HTTP Range header that triggers quadratic-time processing in Starlette's FileResponse Range parsing/merging logic. This enables CPU exhaustion per request, causing denial‑of‑service for endpoints serving files (e.g., StaticFiles or any use of FileResponse). This vulnerability is fixed in 0.49.1.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5
https://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c
https://github.com/Kludex/starlette/releases/tag/0.49.1
https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8

Configurations

No configuration.

History

08 Oct 2026, 11:10

Type	Values Removed	Values Added
Summary		(es) Starlette es un framework/toolkit ASGI ligero. A partir de la versión 0.39.0 y antes de la versión 0.49.1, un atacante no autenticado puede enviar una cabecera HTTP Range manipulada que desencadena un procesamiento de tiempo cuadrático en la lógica de análisis/fusión de rangos de FileResponse de Starlette. Esto permite el agotamiento de la CPU por solicitud, causando denegación de servicio para los puntos finales que sirven archivos (por ejemplo, StaticFiles o cualquier uso de FileResponse). Esta vulnerabilidad está corregida en la versión 0.49.1.

Information

Published : 2025-10-28 21:15

Updated : 2026-10-08 11:10

NVD link : CVE-2025-62727

Mitre link : CVE-2025-62727

CVE.ORG link : CVE-2025-62727

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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