CVE-2025-62727
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
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 7.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.68%
- Percentil entre todas las CVEs puntuadas: 51
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1499.004Application or System Exploitationimpact90 %
Vector CVSS AV:N/AC:L/PR:N (red sin privilegios) indica T1190. El atacante agota CPU con encabezados HTTP Range crafted, causando DoS de aplicación (T1499.004: application exhaustion).
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-407
Referencias
- https://github.com/Kludex/starlette/commit/4ea6e22b489ec388d6004cfbca52dd5b147127c5
- https://github.com/Kludex/starlette/commit/69ed26a85956ef4bd0161807eb27abf49be7cd3c
- https://github.com/Kludex/starlette/releases/tag/0.49.1
- https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
- https://github.com/Kludex/starlette/security/advisories/GHSA-7f5h-v6xp-fcq8
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-62727",
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},
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],
"version": "2.0.3",
"timestamp": "2025-10-28T20:36:34.130234Z"
}
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"cvssMetricV31": [
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
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"exploitabilityScore": 3.9
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"affected": [
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"affectedData": [
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"published": "2025-10-28T21:15:40.447",
"references": [
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"value": "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."
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"lastModified": "2026-06-17T09:52:20.480",
"sourceIdentifier": "security-advisories@github.com"
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