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ChromeWeb browser · Google

CVE-2021-30525

HIGH · 8.8 CVSS v3.1 Published 2021-06-07
Fix available
A fix is available. Upgrade to 91.0.4472.77 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 TabGroups in Google Chrome prior to 91.0.4472.77 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 exists in the TabGroups component of Google Chrome versions prior to 91.0.4472.77. The flaw allows a malicious extension, when combined with a specially crafted HTML page, to access memory after it has been freed, potentially leading to heap corruption and arbitrary code execution.

MitigationUpdate Google Chrome to version 91.0.4472.77 or later. Additionally, exercise caution when installing extensions and only install those from trusted sources to mitigate the social engineering aspect of this attack.

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:< 91.0.4472.77
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. Check installed Chrome version
    Open Chrome, click the three-dot menu, go to Help > About Google Chrome. Alternatively, navigate to chrome://settings/help or run 'google-chrome --version' in terminal.
    Affected if The displayed version is lower than 91.0.4472.77 (e.g., 91.0.4472.76 or earlier)
  2. Check Fedora system version
    Run 'cat /etc/fedora-release' or 'fedora-release' command in terminal to identify the Fedora distribution version.
    Affected if The system runs Fedora 33 or Fedora 34 and has an affected Chrome version installed
  3. Verify TabGroups feature is in use
    Look for the Tab Groups icon in the Chrome tab strip, or check if extensions related to tab grouping have been installed. Navigate to chrome://extensions to inspect installed extensions.
    Affected if TabGroups feature is actively used or tab grouping extensions are installed, as the vulnerability exists within this component

You are affected if you are running Google Chrome version lower than 91.0.4472.77 on Windows, macOS, or Linux, or on Fedora 33/34 systems, particularly when using the TabGroups functionality.

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 91.0.4472.77 or later
Fixed in 91.0.4472.77
Interim mitigation

Update Google Chrome to version 91.0.4472.77 or later. Additionally, exercise caution when installing extensions and only install those from trusted sources to mitigate the social engineering aspect of this attack.

Recommended fix High confidence

Chrome 91.0.4472.77 or later (or latest stable release)

  1. For Chrome browser users: Ensure Chrome auto-updates are enabled, or manually update Chrome by navigating to chrome://settings/help and clicking 'Update Google Chrome' to reach version 91.0.4472.77 or later
  2. For Fedora systems: Run 'sudo dnf update google-chrome-stable' or 'sudo dnf update' to install the patched Chrome package once available from Fedora
  3. Restart the browser after updating to ensure the fix is applied
  4. Verify the version by navigating to chrome://settings/help - it should show version 91.0.4472.77 or higher
Caveat Minimal - this is a security patch upgrade; Chrome's auto-update mechanism typically handles this seamlessly

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

Fix this in Chrome Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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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-2021-30525 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