High severity · published Apr 21, 2026
CVE-2026-3298
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
8.8
CVSS
0.4%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 33% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CP
CPython · Python Software Foundation
before 3.11.16; 3.12.0 before 3.12.14; 3.13.0 before 3.13.14; 3.14.0a1 before 3.14.5rc1; 3.15.0a1 before 3.15.0b1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3298
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3298
github.com
https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d
github.com
https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2
github.com
https://github.com/python/cpython/commit/6c8b85b3f1d83d5697ec19880960e1eacee56688
github.com
https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741
github.com
https://github.com/python/cpython/commit/f5ca38739241fe7a40a4b116d5a8a1364dd6fea7
github.com
https://github.com/python/cpython/issues/148808
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