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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.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
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
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