CVE-2021-30531Network attack vector

Content security policy bypass via crafted HTML

Published Jun 7, 2021 · Updated Aug 3, 2024

Content Security Policy bypass in Google Chrome before 91.0.4472.77 allows remote attackers to evade page restrictions via crafted HTML. Google's public advisory identifies the Content Security Policy component but leaves the faulty enforcement path and rejected policy condition undisclosed. A user must load the attacker-controlled page; the published impact is limited to unauthorized modification of page behavior, with no confidentiality or availability impact.

CVSS severity6.5
Medium
EPSS probability1.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Content Security Policy bypass in Google Chrome before 91.0.4472.77 allows remote attackers to evade page restrictions via crafted HTML. Google's public advisory identifies the Content Security Policy component but leaves the faulty enforcement path and rejected policy condition undisclosed. A user must load the attacker-controlled page; the published impact is limited to unauthorized modification of page behavior, with no confidentiality or availability impact.

The record

CVE
CVE-2021-30531
Published
Jun 7, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Google Chrome
Classifications
T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 7, 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 <91.0.4472.77

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · Google Chromeversion=unspecified <91.0.4472.77

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N

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

T1189Drive-by Compromise

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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