# CVE-2025-62727

## Summary

- **CVE ID:** CVE-2025-62727
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-407
- **Published:** Oct 28, 2025
- **Last Modified:** Mar 13, 2026

## 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.

## Affected Products

- Kludex — starlette (>= 0.39.0, < 0.49.1)

## References

- [CNA](https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8)
- [CNA](https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5)
- [CNA](https://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c)
- [CNA](https://github.com/Kludex/starlette/releases/tag/0.49.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.64%
- **EPSS Percentile:** 48.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._