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CVE-2026-3298— Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes

Quick assessment

Affected
Python Software Foundation CPython
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

CPython是Python基金会的一个用C语言实现的Python解释器。 CPython存在安全漏洞，该漏洞源于asyncio.ProacterEventLoop方法sock_recvfrom_into使用nbytes参数时缺少数据缓冲区边界检查，可能导致数据大于缓冲区大小时发生越界缓冲区写入。

CVSS 8.8 · High EPSS 0.60% · P47

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 5

VendorProduct Version RangeStatus
Python Software Foundation CPython < 3.11.16 affected
3.12.0< 3.12.14 affected
3.13.0< 3.13.14 affected
3.14.0a1< 3.14.5rc1 affected
3.15.0a1< 3.15.0b1 affected
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I. Basic Information for CVE-2026-3298

Vulnerability Information
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Vulnerability Title
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
Source: CVE Program / CVE List V5
Vulnerability Description
The method "sock_recvfrom_into()" of "asyncio.ProacterEventLoop" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. This allowed for an out-of-bounds buffer write if data was larger than the buffer size. Non-Windows platforms are not affected.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存写
Source: CVE Program / CVE List V5
Vulnerability Title
CPython 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
CPython是Python基金会的一个用C语言实现的Python解释器。 CPython存在安全漏洞，该漏洞源于asyncio.ProacterEventLoop方法sock_recvfrom_into使用nbytes参数时缺少数据缓冲区边界检查，可能导致数据大于缓冲区大小时发生越界缓冲区写入。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Python Software Foundation CPython 0 ~ 3.11.16 -

II. Public POCs for CVE-2026-3298

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 10317 chars
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III. Intelligence Information for CVE-2026-3298

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Patches & Fixes for CVE-2026-3298 (4)

News Coverage for CVE-2026-3298 (1)

IV. Related Vulnerabilities

Same product: CPython
Same vendor: Python Software Foundation
Same weakness: CWE-787

V. Comments for CVE-2026-3298

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