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FirefoxWeb browser · Mozilla

CVE-2020-15648

MEDIUM · 6.5 CVSS v3.1 Published 2020-08-10
Fix available
A fix is available. Upgrade to 78.0 / 78.0.2 or later.
See remediation →
72/100
Remediation priority · Elevated
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
Using object or embed tags, it was possible to frame other websites, even if they disallowed framing using the X-Frame-Options header. This vulnerability affects Thunderbird < 78 and Firefox < 78.0.2.

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

The vulnerability allows attackers to embed external websites using object or embed HTML tags, bypassing X-Frame-Options protections that normally prevent clickjacking attacks. This enables UI redress attacks where users can be tricked into clicking unintended actions on framed websites.

MitigationUpdate affected installations to Firefox 78.0.2, Thunderbird 78, or later versions to receive the security patch.

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:< 78.0.2
ThunderbirdApplication
Affected:< 78.0

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
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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. Check Firefox version on Windows
    Open Firefox, click the menu button (three horizontal lines), select Help, then About Firefox. The version number is displayed in the window that opens.
    Affected if The displayed version is below 78.0.2 (for example, 78.0.1, 77.x, or earlier)
  2. Check Firefox version on Linux
    Open a terminal and run: firefox --version
    Affected if The reported version is below 78.0.2 (for example, 78.0.1, 77.x, or earlier)
  3. Check Thunderbird version on Windows
    Open Thunderbird, click the menu button, select Help, then About Thunderbird. The version number is displayed in the window that opens.
    Affected if The displayed version is below 78.0 (for example, 77.x or earlier)
  4. Check Thunderbird version on Linux
    Open a terminal and run: thunderbird --version
    Affected if The reported version is below 78.0 (for example, 77.x or earlier)

You are affected if any installed instance of Firefox is below version 78.0.2 or Thunderbird is below version 78.0.

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 78.0 / 78.0.2 or later
Fixed in 78.078.0.2
Interim mitigation

Update affected installations to Firefox 78.0.2, Thunderbird 78, or later versions to receive the security patch.

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,780
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,848.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2020-15648 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