CVE-2021-30633Known exploitationNetwork attack vector

Sandbox escape via IndexedDB use-after-free

Published Oct 8, 2021 · Updated Oct 21, 2025

Use-after-free in Google Chrome's IndexedDB API before 93.0.4577.82 allows remote attackers to escape the browser sandbox. Google identifies the Indexed DB API as the affected locus but has not disclosed the responsible function or the lifetime error that leaves freed memory reachable. Exploitation requires a compromised renderer process and crafted HTML, and successful escape crosses the renderer sandbox boundary.

CVSS severity9.6
Critical
EPSS probability32.66%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Google Chrome's IndexedDB API before 93.0.4577.82 allows remote attackers to escape the browser sandbox. Google identifies the Indexed DB API as the affected locus but has not disclosed the responsible function or the lifetime error that leaves freed memory reachable. Exploitation requires a compromised renderer process and crafted HTML, and successful escape crosses the renderer sandbox boundary.

The record

CVE
CVE-2021-30633
Published
Oct 8, 2021
Updated
Oct 21, 2025
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities listing
  3. Oct 21, 2025Record 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 <93.0.4577.82

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <93.0.4577.82

Published CVSS scores

9.6NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
6.8NVDAV: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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.

Reported exploitation

Technologies

Your stack

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Your stack

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