# CVE-2025-62727: starlette: Starlette is a lightweight ASGI framework/toolkit

CVE-2025-62727 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2025-62727, released October 28, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-62727
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0080
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 28, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-starlette opensuse-leap 16.0 | 0.41.3-160000.3.1 | [OPENSUSE-SU-2026:20975-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20975-1.md) | Jun 17, 2026 |
| Linux | python-starlette sles 16.0 | 0.41.3-160000.3.1 | [SUSE-SU-2026:22151-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22151-1.md) | Jun 17, 2026 |
| Linux | starlette Debian 13.5 (trixie) | 0.46.1-3+deb13u1 | [DEBIAN-CVE-2025-62727](https://patchblox.com/security/data/fix/linux/debian-cve-2025-62727.md) | Oct 28, 2025 |
| Linux | starlette Debian 14 | 0.50.0-1 | [DEBIAN-CVE-2025-62727](https://patchblox.com/security/data/fix/linux/debian-cve-2025-62727.md) | Oct 28, 2025 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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