CVE-2025-21342Network attack vector

Remote code execution via undisclosed type confusion

Published Feb 6, 2025 · Updated Feb 26, 2026

Type confusion in Microsoft Edge (Chromium-based) before 133.0.3065.51 allows remote attackers to execute code via crafted web content. Microsoft identifies CWE-843 but has not disclosed the affected component or the incompatible-type operation that processes the content. Exploitation requires a user to open the crafted content; no authentication is required, and successful exploitation executes code.

CVSS severity8.8
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

Type confusion in Microsoft Edge (Chromium-based) before 133.0.3065.51 allows remote attackers to execute code via crafted web content. Microsoft identifies CWE-843 but has not disclosed the affected component or the incompatible-type operation that processes the content. Exploitation requires a user to open the crafted content; no authentication is required, and successful exploitation executes code.

The record

CVE
CVE-2025-21342
Published
Feb 6, 2025
Updated
Feb 26, 2026
Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
Classifications
CWE-843, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 6, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 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 <133.0.3065.51

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge (Chromium-based)version=1.0.0.0 <133.0.3065.51

Published CVSS scores

8.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 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-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

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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