Out-of-bounds Write Affecting cpython package, versions [3.11.9,]
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CONAN-CPYTHON-16134974
- published26 Apr 2026
- disclosed21 Apr 2026
- creditUnknown
Introduced: 21 Apr 2026
CVE-2026-3298 (opens in a new tab)How to fix?
A fix was pushed into the master branch but not yet published.
Overview
Affected versions of this package are vulnerable to Out-of-bounds Write through asyncio.AbstractEventLoop.sock_recvfrom_into in the Windows ProactorEventLoop datagram receive path. An attacker can trigger a ValueError-free out-of-bounds receive by supplying an nbytes value larger than the destination buffer length when a program calls sock_recvfrom_into on a UDP socket. This can cause the event loop to read past the end of the provided buffer, leading to process crashes or memory corruption in applications that expose this API to untrusted input.
Notes
- This vulnerability only affects Windows systems and is tied to the
asyncio.ProactorEventLoopdatagram receive path; the selector-based event loops used on non-Windows platforms are not in scope.