CVE-2021-21115Network attack vector

Sandbox escape via PasswordProtectionRequest use-after-free

Published Jan 8, 2021 · Updated Aug 3, 2024

Use-after-free in Google Chrome before 87.0.4280.141 allows remote attackers with renderer control to escape the sandbox via crafted HTML. PasswordProtectionRequest lifetime handling lets Finish() erase the request from pending_requests_ and delete the instance while its method is still executing, after which freed state is accessed. Exploitation requires user interaction with crafted HTML and prior compromise of the renderer process; successful escape breaks browser-process isolation.

CVSS severity9.6
Critical
EPSS probability1.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Google Chrome before 87.0.4280.141 allows remote attackers with renderer control to escape the sandbox via crafted HTML. PasswordProtectionRequest lifetime handling lets Finish() erase the request from pending_requests_ and delete the instance while its method is still executing, after which freed state is accessed. Exploitation requires user interaction with crafted HTML and prior compromise of the renderer process; successful escape breaks browser-process isolation.

The record

CVE
CVE-2021-21115
Published
Jan 8, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1211
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 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

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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 <87.0.4280.141

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <87.0.4280.141

Published CVSS scores

9.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

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.

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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-416Use After Free
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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