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.
Metrics
Affected Vendors & Products
References
History
Tue, 04 Nov 2025 18:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Starlette is a lightweight ASGI framework/toolkit. Prior to 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. | 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. |
| References |
|
Wed, 29 Oct 2025 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Encode
Encode starlette |
|
| Vendors & Products |
Encode
Encode starlette |
Wed, 29 Oct 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
threat_severity
|
Tue, 28 Oct 2025 21:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 28 Oct 2025 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Starlette is a lightweight ASGI framework/toolkit. Prior to 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. | |
| Title | Starlette vulnerable to O(n^2) DoS via Range header merging in starlette.responses.FileResponse | |
| Weaknesses | CWE-407 | |
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: GitHub_M
Published: 2025-10-28T20:14:53.655Z
Updated: 2025-11-04T17:41:42.316Z
Reserved: 2025-10-20T19:41:22.742Z
Link: CVE-2025-62727
Updated: 2025-10-28T20:36:44.968Z
Status : Awaiting Analysis
Published: 2025-10-28T21:15:40.447
Modified: 2025-11-04T18:16:45.480
Link: CVE-2025-62727