CVE-2026-3298
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
- State
- Published
- Severity
- 8.8 High
- Published
- Apr 21, 2026
- Updated
- Aug 13, 2026
- Reserved
- Feb 26, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.8 High | 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 | PSF |
Weaknesses
- CWE-787 Out-of-bounds write
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/pull/148809patch
- https://github.com/python/cpython/issues/148808issue-tracking
- https://mail.python.org/archives/list/security-announce@python.org/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/vendor-advisory
- https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4dpatch
- https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2patch
- https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741patch
- https://github.com/python/cpython/commit/6c8b85b3f1d83d5697ec19880960e1eacee56688patch
- https://github.com/python/cpython/commit/f5ca38739241fe7a40a4b116d5a8a1364dd6fea7patch
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