CVE-2021-30621Network attack vector

Security UI spoofing via crafted Autofill page

Published Sep 3, 2021 · Updated Aug 3, 2024

UI spoofing in Microsoft Edge (Chromium-based) 93.0.961.38 and earlier allows remote attackers to imitate security UI via crafted HTML. The Autofill implementation permits a crafted page to trigger browser UI that presents a deceptive security interface. Exploitation requires the user to open and interact with the page; the documented consequence is UI spoofing rather than data disclosure or code execution.

CVSS severity6.5
Medium
EPSS probability3.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

UI spoofing in Microsoft Edge (Chromium-based) 93.0.961.38 and earlier allows remote attackers to imitate security UI via crafted HTML. The Autofill implementation permits a crafted page to trigger browser UI that presents a deceptive security interface. Exploitation requires the user to open and interact with the page; the documented consequence is UI spoofing rather than data disclosure or code execution.

The record

CVE
CVE-2021-30621
Published
Sep 3, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
Classifications
CWE-290
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge (Chromium-based)version=unspecified

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo