CVE-2021-33096

Local service interruption via malformed guest I/O

Published Feb 9, 2022 · Updated May 5, 2025

Improper shared-resource isolation in Intel 82599 Ethernet Controllers and Adapters allows local users to interrupt service. In direct-assignment or SR-IOV deployments, a guest can issue malformed I/O requests that shared network-on-chip resources fail to isolate, hanging Ethernet data processing or raising PCIe AER events. Low-privilege access to an assigned device or virtual function is required; effects range from a function-level transmit or receive hang to a hypervisor stall or platform reset.

CVSS severity6.5
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper shared-resource isolation in Intel 82599 Ethernet Controllers and Adapters allows local users to interrupt service. In direct-assignment or SR-IOV deployments, a guest can issue malformed I/O requests that shared network-on-chip resources fail to isolate, hanging Ethernet data processing or raising PCIe AER events. Low-privilege access to an assigned device or virtual function is required; effects range from a function-level transmit or receive hang to a hypervisor stall or platform reset.

The record

CVE
CVE-2021-33096
Published
Feb 9, 2022
Updated
May 5, 2025
Vendor
Intel Corporation
Product
Intel 82599 10 Gigabit Ethernet Controller
Classifications
CWE-668, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 9, 2022CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=See references

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Intel Corporation · Intel 82599 10 Gigabit Ethernet Controllerversion=See references

Published CVSS scores

6.5Intel CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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