CVE-2025-62727

Aliases:GHSA-7f5h-v6xp-fcq8ECHO-fc38-da22-1afbPYSEC-2026-1942DEBIAN-CVE-2025-62727
Advisory lineage Upstream: 0 Downstream: 7
Deferred
Published: 28 Oct 2025, 20:14
Last modified:04 Nov 2025, 17:41

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
0.64% LOW
1% probability +0.11%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

28 Oct 2025, 20:14
Published
Vulnerability first disclosed
04 Nov 2025, 17:41
Last Modified
Vulnerability information updated

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 Metrics

  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.64%• Percentile: 48%

Techniques & Countermeasures

  • CWE-407•Inefficient Algorithmic Complexity

    An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

Affected Systems

  • debian•starlette

    < 0.46.1-3+deb13u1 | < 0.50.0-1

  • kludex•starlette

    ≥ 0.39.0, < 0.49.1

  • PyPI•starlette

    ≥ 0.39.0, < 0.49.1

References (9)