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CVE-2026-3298
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
High8.8EPSS 0.39%
- Published
- Updated
- Reserved
- Assigned by
- PSF
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.
Timeline
ID reserved
By PSF
- 54 days later
· 54 days later
Published
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| PSFCNA (assigner) | 4.0 | High8.8 | 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 |
| NVDNVD · Awaiting Analysis | 4.0 | High8.8 | 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/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 |
- EPSS (exploitation in 30 days)
- 0.39% · top 66% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
Affected products
Python Software Foundation · CPython
- affected < 3.11.16
- affected 3.12.0 – < 3.12.14
- affected 3.13.0 – < 3.13.14
- affected 3.14.0a1 – < 3.14.5rc1
- affected 3.15.0a1 – < 3.15.0b1
References (8)
- https://github.com/python/cpython/pull/148809 (opens in a new tab)patch
- https://github.com/python/cpython/issues/148808 (opens in a new tab)issue-tracking
- https://mail.python.org/archives/list/[email protected]/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/ (opens in a new tab)vendor-advisory
- https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d (opens in a new tab)patch
- https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2 (opens in a new tab)patch
- https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741 (opens in a new tab)patch
- https://github.com/python/cpython/commit/6c8b85b3f1d83d5697ec19880960e1eacee56688 (opens in a new tab)patch
- https://github.com/python/cpython/commit/f5ca38739241fe7a40a4b116d5a8a1364dd6fea7 (opens in a new tab)patch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-3298)Record last updated .