CVE-2020-16017Known exploitationNetwork attack vector

Sandbox escape via site-isolation use-after-free

Published Jan 8, 2021 · Updated Oct 21, 2025

Use-after-free in Google Chrome before 86.0.4240.198 allows remote attackers with a compromised renderer to escape its sandbox via crafted HTML. Site-isolation code accesses an object after its memory is freed, but Google has not publicly identified the object or operation. Exploitation requires renderer compromise and user interaction with crafted HTML, and a successful escape crosses the browser sandbox boundary.

CVSS severity9.6
Critical
EPSS probability2.75%
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 86.0.4240.198 allows remote attackers with a compromised renderer to escape its sandbox via crafted HTML. Site-isolation code accesses an object after its memory is freed, but Google has not publicly identified the object or operation. Exploitation requires renderer compromise and user interaction with crafted HTML, and a successful escape crosses the browser sandbox boundary.

The record

CVE
CVE-2020-16017
Published
Jan 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. Jan 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry
  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 <86.0.4240.198

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <86.0.4240.198

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
9.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.6CISA-ADPCVSS: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.

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.

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Reported exploitation

Technologies

Your stack

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Your stack

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