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

Published Apr 21, 2026
·
Updated

The method "sockrecvfrominto()" 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.

Affected Software

1 affected component
Python asyncio.ProactorEventLoop

Event History

Apr 21, 2026
CVE Published
via MITRE·02:45 PM
Data Sourced
via MITRE·02:45 PM
DescriptionWeakness
Data Sourced
via NVD·03:16 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2026-3298?

CVE-2026-3298 has been classified with a significant severity due to the potential for out-of-bounds write vulnerabilities in Windows.

2

How do I fix CVE-2026-3298?

To fix CVE-2026-3298, update to the latest version of the Python asyncio.ProactorEventLoop where the vulnerability has been patched.

3

What systems are affected by CVE-2026-3298?

CVE-2026-3298 affects systems running Windows that utilize the Python asyncio.ProactorEventLoop.

4

What exploitation methods are possible with CVE-2026-3298?

Exploitation of CVE-2026-3298 could allow an attacker to write outside the intended memory bounds, potentially leading to arbitrary code execution.

5

Is CVE-2026-3298 related to Python's asyncio library?

Yes, CVE-2026-3298 specifically relates to the asyncio library in Python, affecting the ProactorEventLoop implementation.

Contact

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