01 Record
CVE-2026-3298
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
HighPUBLISHEDCNA: PSF
CNA base score8.8 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
02 Description
Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.39% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 33.0% of scored records. A rank, not a probability.
- NVD base score
- 8.8 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- 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
- NVD analysis status
- Awaiting Analysis. NVD last modified this record on 2026-10-26.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-04-21 14:45Z6 MO AGO
- Last updated
- 2026-08-13 00:27Z2 MO AGO
- Reserved
- 2026-02-26
- Assigning CNA
- PSF
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.8)
- CNA CVSS vector
- 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
- Weaknesses
- CWE-787Out-of-bounds WriteBase
- Data version
- 5.2
- Document digest
- 14850235119432e1856f8b3a62aacc61e85ae4094dd5c177d8ecf9ae2edf6124
05 Affected products
VendorProductVersionsPlatforms
Python Software FoundationCPython0 to < 3.11.16, 3.12.0 to < 3.12.14, 3.13.0 to < 3.13.14, 3.14.0a1 to < 3.14.5rc1, 3.15.0a1 to < 3.15.0b1—
06 References
- github.comhttps://github.com/python/cpython/pull/148809
- github.comhttps://github.com/python/cpython/issues/148808
- mail.python.orghttps://mail.python.org/archives/list/security-announce@python.org/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/
- github.comhttps://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d
- github.comhttps://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2
- github.comhttps://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741
- github.comhttps://github.com/python/cpython/commit/6c8b85b3f1d83d5697ec19880960e1eacee56688
- github.comhttps://github.com/python/cpython/commit/f5ca38739241fe7a40a4b116d5a8a1364dd6fea7