CVE-2024-12254
Starting in Python 3.12.0, the asyncio._SelectorSocketTransport.writelines() method would not "pause" writing and signal to the Protocol to drain the buffer to the wire once the write buffer reached the "high-water mark". Because of this, Protocols would not periodically drain the write buffer potentially leading to memory exhaustion.
This vulnerability likely impacts a small number of users, you must be using Python 3.12.0 or later, on macOS or Linux, using the asyncio module with protocols, and using .writelines() method which had new zero-copy-on-write behavior in Python 3.12.0 and later. If not all of these factors are true then your usage of Python is unaffected.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 8.7
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 1.87%
- Percentil entre todas las CVEs puntuadas: 79
- 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 access75 % - Impacto principal
T1499.004Application or System Exploitationimpact85 %
Vulnerabilidad remota en asyncio (AV:N/PR:N/UI:N) causando exhaustión de memoria por fallo al drenar buffer en writelines(); DoS por consumo de recursos.
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-400, CWE-770
- CWE-770
Referencias
- https://github.com/python/cpython/commit/71e8429ac8e2adc10084ab5ec29a62f4b6671a82
- https://github.com/python/cpython/commit/9aa0deb2eef2655a1029ba228527b152353135b5
- https://github.com/python/cpython/commit/e991ac8f2037d78140e417cc9a9486223eb3e786
- https://github.com/python/cpython/issues/127655
- https://github.com/python/cpython/pull/127656
- https://mail.python.org/archives/list/security-announce@python.org/thread/H4O3UBAOAQQXGT4RE3E4XQYR5XLROORB/
- http://www.openwall.com/lists/oss-security/2024/12/06/1
- https://security.netapp.com/advisory/ntap-20250404-0010/
JSON original (NVD)
Mostrar
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"published": "2024-12-06T16:15:20.623",
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"weaknesses": [
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"descriptions": [
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"value": "Starting in Python 3.12.0, the asyncio._SelectorSocketTransport.writelines()\n method would not \"pause\" writing and signal to the Protocol to drain \nthe buffer to the wire once the write buffer reached the \"high-water \nmark\". Because of this, Protocols would not periodically drain the write\n buffer potentially leading to memory exhaustion.\n\n\n\n\n\nThis\n vulnerability likely impacts a small number of users, you must be using\n Python 3.12.0 or later, on macOS or Linux, using the asyncio module \nwith protocols, and using .writelines() method which had new \nzero-copy-on-write behavior in Python 3.12.0 and later. If not all of \nthese factors are true then your usage of Python is unaffected."
},
{
"lang": "es",
"value": "Starting de Python 3.12.0, el método asyncio._SelectorSocketTransport.writelines() no \"pausaba\" la escritura ni enviaba señales al protocolo para que vaciara el búfer hacia el cable una vez que el búfer de escritura alcanzaba el \"límite superior\". Debido a esto, los protocolos no vaciaban periódicamente el búfer de escritura, lo que podría provocar el agotamiento de la memoria. Es probable que esta vulnerabilidad afecte a una pequeña cantidad de usuarios. Debes usar Python 3.12.0 o posterior, en macOS o Linux, usar el módulo asyncio con protocolos y usar el método .writelines(), que tenía un nuevo comportamiento de copia cero al escribir en Python 3.12.0 y posterior. Si no se cumplen todos estos factores, tu uso de Python no se ve afectado."
}
],
"lastModified": "2026-07-31T15:16:26.553",
"sourceIdentifier": "cna@python.org"
}