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CVE-2026-3298 | Mondoo Vulnerability Intelligence

Vulnerability IntelligenceCVE-2026-3298

CVE-2026-3298

HIGH8.8

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

Published Apr 21, 2026

Modified 2 weeks ago

Details

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.

References

https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d

https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2

https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741

https://github.com/python/cpython/issues/148808

https://github.com/python/cpython/pull/148809

https://mail.python.org/archives/list/security-announce@python.org/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/

https://www.cve.org/CVERecord?id=CVE-2026-3298

CVSS Analysis

CVSS v4.0

8.8

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Attack Requirements

NoneAT:N

Privileges Required

NonePR:N

User Interaction

NoneUI:N

Vulnerable System

Vuln. Confidentiality

LowVC:L

Vuln. Integrity

LowVI:L

Vuln. Availability

HighVA:H

Subsequent System

Subseq. Confidentiality

NoneSC:N

Subseq. Integrity

NoneSI:N

Subseq. Availability

NoneSA:N

8.8/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

Weakness Type (CWE)

Memory Safety

Out-of-bounds Write

Ecosystems

Timeline

PublishedApr 21, 2026

ModifiedMay 12, 2026