PT-2026-33988 · Python · Cpython

Ggautomaton + 2 · Published 2026-04-21 · Updated 2026-04-21 · CVE-2026-3298

NVD

CVSS v4.0

8.8

High

AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/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

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.

Fix

Memory Corruption

Weakness Enumeration

CWE-787

Related Identifiers

CVE-2026-3298

Affected Products

Cpython

References · 9

• https://github.com/python/cpython/pull/148809 · Patch
• https://mail.python.org/archives/list/[e-mail]/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-3298 · Security Note
• https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741 · Note
• https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d · Note
• https://twitter.com/CVEnew/status/2046620100136956257 · Twitter Post
• https://twitter.com/infoflowcloud/status/2046622318709887106 · Twitter Post
• https://github.com/python/cpython/issues/148808 · Note
• https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2 · Note