dbcve.org
Firefox EsrWeb browser · Mozilla

CVE-2020-6828

HIGH · 7.5 CVSS v3.1 Published 2020-04-24
Fix available
A fix is available. Upgrade to 68.7.0 or later.
See remediation →
84/100
Remediation priority · High
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
A malicious Android application could craft an Intent that would have been processed by Firefox for Android and potentially result in a file overwrite in the user's profile directory. One exploitation vector for this would be to supply a user.js file providing arbitrary malicious preference values. Control of arbitrary preferences can lead to sufficient compromise such that it is generally equivalent to arbitrary code execution.<br> *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 68.7.

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

A malicious Android application can craft and send specially crafted Intents to Firefox for Android, allowing file overwrite in the user's profile directory. Specifically, a malicious app can overwrite or create a user.js file with arbitrary preference values, which can lead to compromise equivalent to arbitrary code execution.

MitigationUpdate Firefox for Android to version 68.7 or later. As a defense-in-depth measure, users should only install applications from trusted sources to reduce the risk of malicious Intents being sent to Firefox.

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
Firefox EsrWeb browser
Affected:< 68.7.0

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
None
Integrity
High
Availability
None

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

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. Identify if Firefox for Android is installed
    Check device applications for Mozilla Firefox (not Firefox Focus or Firefox Preview). On Android, go to Settings > Apps > Mozilla Firefox, or run: `adb shell pm list packages | grep org.mozilla.firefox`
    Affected if The package org.mozilla.firefox is present on the device
  2. Determine installed Firefox for Android version
    Open Firefox for Android, type 'about:' in the address bar and scroll to find the version number, or use: `adb shell dumpsys package org.mozilla.firefox | grep versionName`
    Affected if Version is below 68.7.0 (for example, 68.6.0, 68.5.0, etc.)
  3. Verify the attack surface exists
    Confirm that other applications can send Intents to Firefox. This is default Android behavior unless restricted. A malicious local app with intent-sending capability could exploit this if Firefox is vulnerable.
    Affected if Firefox for Android version is below 68.7.0 AND other applications are allowed to send Intents to it (standard Android permission model)
  4. Check for user.js file presence
    If Firefox has been run, a user.js file may exist in the Firefox profile directory. On a rooted device: `adb shell find /data/data/org.mozilla.firefox -name 'user.js' 2>/dev/null`. On non-rooted, this is not directly accessible.
    Affected if A user.js file exists with unexpected or suspicious preference entries (requires profile access)

You are affected if Firefox for Android (Esr) version is below 68.7.0 and a malicious application on the same device can send Intents to Firefox.

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.

From vendor data
Upgrade available Upgrade to 68.7.0 or later
Fixed in 68.7.0
Interim mitigation

Update Firefox for Android to version 68.7 or later. As a defense-in-depth measure, users should only install applications from trusted sources to reduce the risk of malicious Intents being sent to Firefox.

Fix this in Firefox Esr Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $910
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,456.

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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-2020-6828 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