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ChromeWeb browser · Google

CVE-2021-30550

HIGH · 8.8 CVSS v3.1 Published 2021-06-15
Fix available
A fix is available. Upgrade to 91.0.4472.101 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Use after free in Accessibility in Google Chrome prior to 91.0.4472.101 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via a crafted HTML page.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A use-after-free vulnerability in Google Chrome's Accessibility component allows a remote attacker to potentially exploit heap corruption. The attack requires tricking a user into installing a malicious extension and then visiting a crafted HTML page, enabling the attacker to execute code in the context of the browser.

MitigationUpdate Google Chrome to version 91.0.4472.101 or later. Additionally, enforce policies that restrict extension installation to trusted sources only from the Chrome Web Store.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ChromeWeb browser
Affected:< 91.0.4472.101
FedoraOperating system
Affected:= 33= 34

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Chrome version
    Navigate to chrome://settings/help or run 'google-chrome --version' in terminal
    Affected if Version is earlier than 91.0.4472.101
  2. Identify operating system
    Run 'cat /etc/os-release' or check system information
    Affected if Running Fedora 33 or Fedora 34 with any Chrome version in the affected range
  3. Verify extension installation policy
    Check Chrome policies at chrome://policy or inspect /etc/opt/chrome/policies/ on managed devices
    Affected if Policy allows installation of extensions from sources other than the Chrome Web Store
  4. Review installed extensions
    Navigate to chrome://extensions and compare installed extensions against trusted sources
    Affected if Any extension is installed from an untrusted or unknown source, especially if not from the Chrome Web Store
  5. Check if Accessibility feature is active
    Observe if the Accessibility API is being accessed or run 'chrome://accessibility' to view accessibility tree
    Affected if Accessibility features are enabled and actively being used by the browser

You are affected if Chrome version is below 91.0.4472.101 AND a malicious extension from an untrusted source is installed and the user visits a crafted HTML page that triggers the Accessibility component use-after-free.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 91.0.4472.101 or later
Fixed in 91.0.4472.101
Interim mitigation

Update Google Chrome to version 91.0.4472.101 or later. Additionally, enforce policies that restrict extension installation to trusted sources only from the Chrome Web Store.

Recommended fix High confidence

Chrome 91.0.4472.101 or later

  1. Upgrade Google Chrome to version 91.0.4472.101 or later
  2. On Fedora systems, run 'sudo dnf update google-chrome-stable' to apply the security update
  3. Restart Chrome after updating to ensure the fix is applied
  4. Verify the version by navigating to chrome://settings/help to confirm version 91.0.4472.101 or newer is installed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Chrome Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,168.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-30550 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data