VULNERABILITY INTELLIGENCE
CVE-2025-62727
CVSS score7.5 HIGH
EPSS probability0.80%
CISA KEVNot currently listed
Published2025-10-28
Last modified2026-10-08
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Description
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.
Weakness classification
- CWE-407: Inefficient Algorithmic Complexity