VulnerabilityPublished 6 Feb 2025Updated 13 Feb 2026

CVE-2025-21404: Microsoft Edge (Chromium-based) · The UI Performs the Wrong Action

Affects Microsoft Edge (Chromium-based)Source CVE Database V5

Not known to be exploited · CVSS 4.3 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.0% chance of exploitation in 30 days – higher than 64% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C

Base metrics

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Temporal metrics

Exploit Code Maturity: Unproven
Remediation Level: Official Fix
Report Confidence: Confirmed

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.
Exploit Code Maturity: Unproven: No exploit code is available, or an exploit is theoretical.
Remediation Level: Official Fix: A complete vendor solution is available. Either the vendor has issued an official patch, or an upgrade is available.
Report Confidence: Confirmed: Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Microsoft Microsoft Edge (Chromium-based)	Affected =1.0.0.0	Fixed in–

AI-suggested

Immediately audit and inventory all Microsoft Edge installations to identify any running the affected version 1.0.0.0 and prioritize their upgrade or replacement.
Until a patch is released, restrict the use of the vulnerable Edge version through application control policies or endpoint management solutions.
Enhance user awareness training focused on recognizing suspicious UI behavior and phishing attempts, emphasizing caution with unexpected browser prompts or actions.
Implement multi-factor authentication (MFA) on critical systems to reduce the impact of potential credential theft resulting from spoofing attacks.
Monitor network traffic and endpoint logs for unusual browser behavior or user actions that could indicate exploitation attempts.
Coordinate with Microsoft for timely updates and apply patches as soon as they become available.
Consider deploying browser security extensions or tools that can detect or block UI spoofing or phishing attempts.
For high-risk environments, consider temporarily using alternative browsers until the vulnerability is addressed.
Integrate this vulnerability into incident response playbooks to ensure rapid detection and response if exploitation is suspected.

Description

Microsoft Edge (Chromium-based) Spoofing Vulnerability

Impact

For European organizations, the primary impact of CVE-2025-21404 lies in the potential for user deception through UI spoofing, which can lead to unauthorized actions being performed unknowingly by users. While the vulnerability does not directly compromise confidentiality or availability, the integrity of user interactions is at risk, potentially enabling attackers to manipulate browser behavior to facilitate phishing, credential theft, or unauthorized transactions. Organizations relying heavily on Microsoft Edge, especially version 1.0.0.0, may face increased risk of targeted social engineering attacks exploiting this flaw. Critical sectors such as finance, government, and healthcare could be particularly vulnerable if attackers use this vulnerability to bypass user trust mechanisms. The absence of known exploits reduces immediate risk, but the potential for future exploitation necessitates proactive measures. Additionally, the requirement for user interaction means that user training and awareness are crucial to mitigate impact. The vulnerability could also undermine user confidence in browser security if exploited at scale.

CWE-449The UI Performs the Wrong Action (opens in a new tab)
Base weakness
The UI performs the wrong action with respect to the user's request.
CWE-451User Interface (UI) Misrepresentation of Critical Information (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The user interface (UI) does not properly represent critical information to the user, allowing the information - or its source - to be obscured or spoofed. This is often a component in phishing attacks.
Implementation · Input Validation
Perform data validation (e.g. syntax, length, etc.) before interpreting the data.
Architecture and Design · Output Encoding
Create a strategy for presenting information, and plan for how to display unusual characters.
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
Attack patterns
Spear Phishing (opens in a new tab)
Mobile Phishing (opens in a new tab)
Phishing (opens in a new tab)
Resource Location Spoofing (opens in a new tab)
Action Spoofing (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21404 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Feb 2026, 08:50 UTC

WeaknessesCWE-449, CWE-451

Technical details

References

Community reviews

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