CVE-2021-30528Public exploitNetwork attack vector

Sandbox escape via stale authenticator callback

Published Jun 7, 2021 · Updated Aug 3, 2024

Use-after-free in Chrome for Android before 91.0.4472.77 allows remote attackers controlling a renderer to escape the browser sandbox. InternalAuthenticator stores a native pointer in a Java callback; destroying its iframe frees the native object while the callback retains and later dereferences that stale pointer. Exploitation requires a crafted page, prior renderer compromise, and a credit card saved in the user's Google account, and grants Chrome application privileges.

CVSS severity8.8
High
EPSS probability1.35%
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 Chrome for Android before 91.0.4472.77 allows remote attackers controlling a renderer to escape the browser sandbox. InternalAuthenticator stores a native pointer in a Java callback; destroying its iframe frees the native object while the callback retains and later dereferences that stale pointer. Exploitation requires a crafted page, prior renderer compromise, and a credit card saved in the user's Google account, and grants Chrome application privileges.

The record

CVE
CVE-2021-30528
Published
Jun 7, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1404
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 7, 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 <91.0.4472.77

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <91.0.4472.77

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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.

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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1404Exploitation for Privilege Escalation

Public exploit references

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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