CVE-2021-38017Network attack vector

Navigation bypass via sandboxed external-protocol requests

Published Dec 23, 2021 · Updated Aug 4, 2024

Insufficient iframe sandbox enforcement in Google Chrome before 96.0.4664.45 allows remote attackers to bypass navigation restrictions. The browser-layer external-protocol handler accepts navigation from a sandboxed iframe without requiring allow-popups, allow-top-level-navigation, or user-activation permission. A victim must load a crafted HTML page; successful exploitation hands navigation to an external application despite the iframe sandbox.

CVSS severity8.8
High
EPSS probability0.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient iframe sandbox enforcement in Google Chrome before 96.0.4664.45 allows remote attackers to bypass navigation restrictions. The browser-layer external-protocol handler accepts navigation from a sandboxed iframe without requiring allow-popups, allow-top-level-navigation, or user-activation permission. A victim must load a crafted HTML page; successful exploitation hands navigation to an external application despite the iframe sandbox.

The record

CVE
CVE-2021-38017
Published
Dec 23, 2021
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-863, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=unspecified <96.0.4664.45

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <96.0.4664.45

Published CVSS scores

8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P

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-863Incorrect Authorization
T1204.001User Execution: Malicious Link

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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