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.
CVSS breakdown
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected products
- Kludex / starlette>= 0.39.0, < 0.49.1 – >= 0.39.0, < 0.49.1
References
- VENDOR_ADVISORYhttps://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
- PATCHhttps://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5
- PATCHhttps://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c
- PATCHhttps://github.com/Kludex/starlette/releases/tag/0.49.1