CVE-2021-4320Network attack vector

Arbitrary memory read and write via font selection

Published Jul 28, 2023 · Updated Feb 13, 2025

Use-after-free in Blink in Google Chrome before 92.0.4515.107 allows remote attackers to perform arbitrary memory reads and writes. The failure occurs in content::FontAccessManagerImpl::DidChooseLocalFonts, which accesses an object after its lifetime ends during local-font selection. Exploitation requires a crafted HTML page, user interaction, and an already compromised renderer; success permits arbitrary reads and writes within the browser process.

CVSS severity8.8
High
EPSS probability0.66%
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 Blink in Google Chrome before 92.0.4515.107 allows remote attackers to perform arbitrary memory reads and writes. The failure occurs in content::FontAccessManagerImpl::DidChooseLocalFonts, which accesses an object after its lifetime ends during local-font selection. Exploitation requires a crafted HTML page, user interaction, and an already compromised renderer; success permits arbitrary reads and writes within the browser process.

The record

CVE
CVE-2021-4320
Published
Jul 28, 2023
Updated
Feb 13, 2025
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=92.0.4515.107 <92.0.4515.107

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=92.0.4515.107 <92.0.4515.107

Published CVSS scores

8.8NISTCVSS: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 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.

Technologies

Your stack

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Your stack

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