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CWE

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CVE-2025-62727

Published: Oct 28, 2025

Modified: Nov 4, 2025

PUBLISHED

CVSS v3.1

7.5

HIGH

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.

Vendor	Product	Versions
Kludex	starlette	affected `>= 0.39.0, < 0.49.1`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

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

References

https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8

x_refsource_CONFIRM

https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5

x_refsource_MISC

https://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c

x_refsource_MISC

https://github.com/Kludex/starlette/releases/tag/0.49.1

x_refsource_MISC

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