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Improper Access ControlWeakness · CWE-284

CVE-2024-45489

CRITICAL · 9.8 CVSS v3.1 Published 2024-09-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Arc before 2024-08-26 allows remote code execution in JavaScript boosts. Boosts that run JavaScript cannot be shared by default; however (because of misconfigured Firebase ACLs), it is possible to create or update a boost using another user's ID. This installs the boost in the victim's browser and runs arbitrary Javascript on that browser in a privileged context. NOTE: this is a no-action cloud vulnerability with zero affected users.

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 · high confidence

Arc browser before 2024-08-26 contains a critical vulnerability in its JavaScript boosts feature where misconfigured Firebase ACLs allow attackers to create or update boosts using another user's ID. This enables installation of malicious boosts in victims' browsers and execution of arbitrary JavaScript in a privileged context, achieving remote code execution.

MitigationThe vulnerability was patched in the 2024-08-26 release; ensure Arc browser is updated to this version or later. Verify Firebase ACL configurations to prevent unauthorized boost manipulation.

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

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 Arc browser installed version
    Open Arc browser, click the Arc logo in the top-left corner, select 'About Arc' from the menu, and note the version number and build date displayed in the dialog.
    Affected if The version shown is earlier than the 2024-08-26 release or shows a build date before August 26, 2024.
  2. Verify build date against patch release
    In the 'About Arc' dialog, locate the build date or version string. Cross-reference with The Browser Company's release notes indicating the 2024-08-26 patch date.
    Affected if The build date is on or before August 25, 2024, indicating an unpatched version.
  3. Identify if JavaScript boosts feature is in use
    Open Arc settings by pressing Cmd+, and navigate to the 'Boosts' section. Review any existing boosts listed there to determine if custom JavaScript enhancements have been created or enabled.
    Affected if Any custom JavaScript boosts are present in the browser, as these could have been created or modified by an attacker exploiting the Firebase ACL flaw.
  4. Inspect boost configuration files
    On macOS, examine the Arc application support directory at ~/Library/Application Support/Arc/ for any boost-related configuration files or scripts that may have been externally introduced.
    Affected if Unexpected or unfamiliar boost scripts are found that were not intentionally created by the user.

A user is affected if their Arc browser version predates the August 26, 2024 patch AND they have used the JavaScript boosts feature, making them potentially vulnerable to malicious boost injection via the Firebase ACL misconfiguration.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

The vulnerability was patched in the 2024-08-26 release; ensure Arc browser is updated to this version or later. Verify Firebase ACL configurations to prevent unauthorized boost manipulation.

Recommended fix High confidence
  1. No action required. This is a cloud/backend vulnerability that has been addressed by the vendor. The official description states: 'this is a no-action cloud vulnerability with zero affected users.'
  2. If you are using Arc browser, ensure you are using the latest version from https://arc.net for best security practices, though this specific vulnerability required no user action.

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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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-2024-45489 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
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