CVE-2021-42308Network attack vector

Remote spoofing via crafted web content

Published Nov 24, 2021 · Updated Aug 19, 2026

Spoofing in Microsoft Edge (Chromium-based) before 96.0.1054.29 allows remote attackers to misrepresent security-sensitive web content. Microsoft has not disclosed the browser component or operation that mishandles the crafted content. Exploitation requires enticing a user to open a specially crafted web page, and the reported consequence is integrity impact through deceptive presentation rather than data disclosure or service interruption.

CVSS severity7.5
High
EPSS probability1.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Spoofing in Microsoft Edge (Chromium-based) before 96.0.1054.29 allows remote attackers to misrepresent security-sensitive web content. Microsoft has not disclosed the browser component or operation that mishandles the crafted content. Exploitation requires enticing a user to open a specially crafted web page, and the reported consequence is integrity impact through deceptive presentation rather than data disclosure or service interruption.

The record

CVE
CVE-2021-42308
Published
Nov 24, 2021
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
Classifications
CWE-290
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record 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=1.0.0.0 <96.0 1954.29

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge (Chromium-based)version=1.0.0.0 <96.0 1954.29

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1MicrosoftCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing

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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