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FirefoxWeb browser · Mozilla

CVE-2019-11760

HIGH · 8.8 CVSS v3.1 Published 2020-01-08
Fix available
A fix is available. Upgrade to 68.2 / 70.0 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
A fixed-size stack buffer could overflow in nrappkit when doing WebRTC signaling. This resulted in a potentially exploitable crash in some instances. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

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 fixed-size stack buffer overflow vulnerability exists in nrappkit during WebRTC signaling processing. The overflow occurs due to insufficient bounds checking when handling signaling data, potentially allowing an attacker to overwrite adjacent stack memory and cause a crash or achieve code execution.

MitigationUpgrade to Firefox 70+, Thunderbird 68.2+, or Firefox ESR 68.2+ to obtain the patched nrappkit library with proper buffer size validation during WebRTC signaling.

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:< 70.0
Firefox EsrWeb browser
Affected:< 68.2
Ubuntu LinuxOperating system
Affected:= 16.04
ThunderbirdApplication
Affected:< 68.2

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 Firefox version
    Run 'firefox --version' or go to Help > About Firefox to view the installed version number
    Affected if Version is below 70.0 (for regular Firefox) or below 68.2 (for Firefox ESR)
  2. Check Thunderbird version
    Run 'thunderbird --version' or go to Help > About Thunderbird to view the installed version number
    Affected if Version is below 68.2
  3. Verify WebRTC is enabled
    In Firefox/Thunderbird, go to about:config and check if media.peerconnection.enabled is set to true (default is true)
    Affected if WebRTC (media.peerconnection.enabled) is enabled - this is the attack surface for the nrappkit signaling flaw
  4. Check for vulnerable nrappkit library on Ubuntu
    Run 'dpkg -l | grep nrappkit' or 'find /usr -name "*nrappkit*"' to locate the nrappkit library
    Affected if The nrappkit library is present on Ubuntu 16.04 systems

You are affected if you run Firefox below 70.0 (or ESR below 68.2), or Thunderbird below 68.2, with WebRTC enabled, or have the nrappkit library on Ubuntu 16.04.

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 68.2 / 70.0 or later
Fixed in 68.270.0
Interim mitigation

Upgrade to Firefox 70+, Thunderbird 68.2+, or Firefox ESR 68.2+ to obtain the patched nrappkit library with proper buffer size validation during WebRTC signaling.

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

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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-2019-11760 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