CVE-2021-38010Network attack vector

Site-isolation bypass via flawed service-worker handling

Published Dec 23, 2021 · Updated Aug 4, 2024

Inappropriate service-worker handling in Google Chrome before 96.0.4664.45 allows remote attackers to bypass site isolation. Google identifies the service-worker implementation but has not published the incorrect operation that lets crafted HTML cross the boundary. Exploitation requires prior renderer compromise and defeats origin separation without a reported browser sandbox escape or host-code execution.

CVSS severity6.5
Medium
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Inappropriate service-worker handling in Google Chrome before 96.0.4664.45 allows remote attackers to bypass site isolation. Google identifies the service-worker implementation but has not published the incorrect operation that lets crafted HTML cross the boundary. Exploitation requires prior renderer compromise and defeats origin separation without a reported browser sandbox escape or host-code execution.

The record

CVE
CVE-2021-38010
Published
Dec 23, 2021
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
T1211
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

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

T1211Exploitation for Defense Evasion

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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