Variant weakness

Draft

CWE-422: Unprotected Windows Messaging Channel ('Shatter')

The product does not properly verify the source of a message in the Windows Messaging System while running at elevated privileges, creating an alternate channel through which an attacker can directly send a message to the product.

Last updated May 1, 2026

2

Recorded CVEs

With this primary weakness

0

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Variant

Abstraction

MITRE classification

Overview

CWE-422 (Unprotected Windows Messaging Channel ('Shatter')) is a variant-level software weakness catalogued by MITRE in the Common Weakness Enumeration (CWE). It describes a recurring type of mistake that can lead to exploitable security vulnerabilities.

Real-world CVEs

2 recorded CVEs are caused by CWE-422 (Unprotected Windows Messaging Channel ('Shatter')). The highest-severity and most recent are shown first. 0 new CWE-422 CVEs have been recorded so far in 2026 (2 in 2025).

Common consequences

What can happen when CWE-422 is exploited.

Gain Privileges or Assume Identity, Bypass Protection Mechanism

Affects: Access Control

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Architecture and Design

How to prevent it

Practical mitigations for CWE-422, grouped by where in the lifecycle they apply.

Architecture and Design

Always verify and authenticate the source of the message.

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-2002-0971 — Bypass GUI and access restricted dialog box.
CVE-2002-1230 — Gain privileges via Windows message.
CVE-2003-0350 — A control allows a change to a pointer for a callback function using Windows message.
CVE-2003-0908 — Product launches Help functionality while running with raised privileges, allowing command execution using Windows message to access "open file" dialog.
CVE-2004-0213 — Attacker uses Shatter attack to bypass GUI-enforced protection for CVE-2003-0908.
CVE-2004-0207 — User can call certain API functions to modify certain properties of privileged programs.

Terminology & mappings

Mapped taxonomies

PLOVER: Unprotected Windows Messaging Channel ('Shatter')
Software Fault Patterns: Missing endpoint authentication (SFP30)

Frequently asked questions

Common questions about CWE-422.

What is CWE-422?

The product does not properly verify the source of a message in the Windows Messaging System while running at elevated privileges, creating an alternate channel through which an attacker can directly send a message to the product.

What CVEs are caused by CWE-422?

2 recorded CVEs are attributed to CWE-422, including CVE-2025-20094, CVE-2025-22894.

How do you prevent CWE-422?

Always verify and authenticate the source of the message.

What are the consequences of CWE-422?

Exploiting CWE-422 can lead to: Gain Privileges or Assume Identity, Bypass Protection Mechanism.

Is CWE-422 actively exploited?

2 recorded CVEs are caused by CWE-422; none are currently in CISA's KEV catalog of actively exploited flaws.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

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