CVE-2021-21191Network attack vector

Heap corruption via WebRTC use-after-free

Published Mar 16, 2021 · Updated Aug 3, 2024

Use-after-free in Google Chrome WebRTC before 89.0.4389.90 allows remote attackers to corrupt heap memory through crafted HTML. The WebRTC component accesses an object after its lifetime ends, but Google keeps the underlying bug details restricted and has not identified the affected function. A user must load the crafted page; the public record limits the consequence to potentially exploitable heap corruption and does not claim a sandbox escape.

CVSS severity8.8
High
EPSS probability1.37%
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 Google Chrome WebRTC before 89.0.4389.90 allows remote attackers to corrupt heap memory through crafted HTML. The WebRTC component accesses an object after its lifetime ends, but Google keeps the underlying bug details restricted and has not identified the affected function. A user must load the crafted page; the public record limits the consequence to potentially exploitable heap corruption and does not claim a sandbox escape.

The record

CVE
CVE-2021-21191
Published
Mar 16, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 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 <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

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.

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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