FirefoxWeb browser · Mozilla
CVE-2020-6800
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 · uneditedMozilla developers and community members reported memory safety bugs present in Firefox 72 and Firefox ESR 68.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or browser-like contexts. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.
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 confidenceMemory safety bugs in Firefox 72 and Firefox ESR 68.4 caused memory corruption that could potentially be exploited for arbitrary code execution. The vulnerabilities affect Thunderbird, Firefox, and Firefox ESR across multiple versions.
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
< 73.0
Firefox EsrWeb browser
< 68.5.0
Ubuntu LinuxOperating system
= 16.04= 18.04= 19.10< 68.5.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check if Mozilla Firefox is installedRun 'firefox --version' or check the application version through the Firefox about dialog (Help > About Firefox)Affected if Installed version is earlier than 73.0 (for example, 72.x)
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Check if Mozilla Firefox ESR is installedRun 'firefox --version' or check the application version through Firefox ESR about dialog. On Linux, also check via package manager: 'dpkg -l | grep firefox-esr' or 'rpm -qa | grep firefox-esr'Affected if Installed version is earlier than 68.5.0 (for example, 68.4.x)
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Check if Mozilla Thunderbird is installedRun 'thunderbird --version' or check the application version through Thunderbird about dialog (Help > About Thunderbird). On Linux, also check via package manager: 'dpkg -l | grep thunderbird' or 'rpm -qa | grep thunderbird'Affected if Installed version is earlier than 68.5.0 (for example, 68.4.x)
You are affected if any Firefox version is below 73.0, or any Firefox ESR or Thunderbird version is below 68.5.0, and the browser/email client is actively used (the memory corruption occurs during normal operation of the affected versions).
Generated from the published advisory. Verify against your own configuration.
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 data68.5.073.0
Update to Thunderbird 68.5+, Firefox 73+, or Firefox ESR 68.5+ to patch the memory corruption vulnerabilities.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-6800 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-6800 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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