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FirefoxWeb browser · Mozilla

CVE-2018-12391

HIGH · 8.8 CVSS v3.0 Published 2019-02-28
Fix available
A fix is available. Upgrade to 60.3 / 63.0 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
During HTTP Live Stream playback on Firefox for Android, audio data can be accessed across origins in violation of security policies. Because the problem is in the underlying Android service, this issue is addressed by treating all HLS streams as cross-origin and opaque to access. *Note: this issue only affects Firefox for Android. Desktop versions of Firefox are unaffected.*. This vulnerability affects Firefox < 63, Firefox ESR < 60.3, and Thunderbird < 60.3.

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

During HTTP Live Stream (HLS) playback on Firefox for Android, audio data can be accessed across origins in violation of same-origin policy. The vulnerability exists in how the underlying Android service handles HLS streams, allowing cross-origin audio access. The fix treats all HLS streams as cross-origin and opaque to prevent this access.

MitigationUpdate Firefox for Android to version 63 or later, Firefox ESR to 60.3 or later, or Thunderbird to 60.3 or later. This is a client-side vulnerability affecting only Android devices.

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
FirefoxWeb browser
Affected:< 63.0
Firefox EsrWeb browser
Affected:< 60.3
ThunderbirdApplication
Affected:< 60.3

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:3.0/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. Identify if running Firefox on Android
    Check the device type and browser. On Android, go to Settings > Apps > Firefox or check the user-agent string in the browser. This vulnerability specifically affects Firefox for Android, not desktop Firefox.
    Affected if The device is running Firefox for Android (mobile/target device)
  2. Check Firefox version number
    On Android Firefox, tap the three dots menu > Help > About Firefox, or check the app version in Google Play Store or Settings > Apps > Firefox. Note the version number displayed.
    Affected if The installed version is less than 63.0 (for standard Firefox Android)
  3. Check Firefox ESR version if applicable
    If using Firefox ESR (enterprise/extended support release), verify the version via Help > About Firefox. ESR versions are typically used on desktop but may appear in some Android configurations.
    Affected if Using Firefox ESR with version less than 60.3
  4. Check Thunderbird version if applicable
    If Thunderbird is installed on the Android device, verify the version via Settings > Apps > Thunderbird > App info, or Help > About Thunderbird.
    Affected if Using Thunderbird with version less than 60.3 on Android
  5. Verify HLS playback is in use
    The vulnerability only affects HTTP Live Stream (HLS) playback. Check browser activity or logs for recent HLS stream access. On Android, HLS streams typically have .m3u8 extensions or use HLS protocol.
    Affected if HLS audio/video streams have been played recently on the affected Firefox/Thunderbird Android app

A user is affected if they are running Firefox for Android (or Thunderbird on Android) with a version lower than 63.0 (or ESR/Thunderbird below 60.3) and have played HLS streams, allowing potential cross-origin audio data access.

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 60.3 / 63.0 or later
Fixed in 60.363.0
Interim mitigation

Update Firefox for Android to version 63 or later, Firefox ESR to 60.3 or later, or Thunderbird to 60.3 or later. This is a client-side vulnerability affecting only Android devices.

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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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-2018-12391 in production — separate from our analysis above.

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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