CVE-2022-35838Network attack vector

Service interruption via undisclosed HTTP/3 flaw

Published Sep 13, 2022 · Updated Mar 11, 2025

Denial of service in HTTP/3 support in Microsoft Windows 11 version 21H2 and Windows Server 2022 allows remote attackers to interrupt service. Microsoft has not published the vulnerable function or the operation it performs incorrectly when processing untrusted HTTP/3 traffic. No authentication or user interaction is required, and the reported consequence is limited to availability.

CVSS severity7.5
High
EPSS probability2.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in HTTP/3 support in Microsoft Windows 11 version 21H2 and Windows Server 2022 allows remote attackers to interrupt service. Microsoft has not published the vulnerable function or the operation it performs incorrectly when processing untrusted HTTP/3 traffic. No authentication or user interaction is required, and the reported consequence is limited to availability.

The record

CVE
CVE-2022-35838
Published
Sep 13, 2022
Updated
Mar 11, 2025
Vendor
Microsoft
Product
Windows 11 version 21H2
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 13, 2022CVE publishedPublication date reported by the CVE source.
  2. Mar 11, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0 <10.0.22000.978

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.978
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.1006

Published CVSS scores

7.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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