CVE-2021-21193Known exploitationNetwork attack vector

Heap corruption via Blink use-after-free

Published Mar 16, 2021 · Updated Oct 21, 2025

Use-after-free in Google Chrome before 89.0.4389.90 allows remote attackers to corrupt heap memory through a crafted HTML page. Google identifies Blink as the affected component but has not disclosed the freed object's type or the lifetime operation that permits its later reuse. Successful exploitation compromises confidentiality, integrity, and availability within Chrome's sandbox; it requires a user to load attacker-controlled HTML.

CVSS severity8.8
High
EPSS probability9.87%
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 before 89.0.4389.90 allows remote attackers to corrupt heap memory through a crafted HTML page. Google identifies Blink as the affected component but has not disclosed the freed object's type or the lifetime operation that permits its later reuse. Successful exploitation compromises confidentiality, integrity, and availability within Chrome's sandbox; it requires a user to load attacker-controlled HTML.

The record

CVE
CVE-2021-21193
Published
Mar 16, 2021
Updated
Oct 21, 2025
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2021Exploitation reportedGoogle reports exploitation in the wild
  2. Mar 16, 2021CVE publishedPublication date reported by the CVE source.
  3. Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry
  4. 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 <89.0.4389.90

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <89.0.4389.90

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
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.

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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 exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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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