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FirefoxWeb browser · Mozilla

CVE-2017-7804

HIGH · 7.5 CVSS v3.0 Published 2018-06-11
Fix available
A fix is available. Upgrade to 52.3.0 / 55.0 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
The destructor function for the "WindowsDllDetourPatcher" class can be re-purposed by malicious code in concert with another vulnerability to write arbitrary data to an attacker controlled location in memory. This can be used to bypass existing memory protections in this situation. Note: This attack only affects Windows operating systems. Other operating systems are not affected. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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 use-after-free style vulnerability in the WindowsDllDetourPatcher's destructor allows malicious code combined with another vulnerability to write arbitrary data to attacker-controlled memory locations, bypassing existing memory protection mechanisms. This is a privilege escalation/auxiliary bug requiring another flaw to be weaponized.

MitigationUpdate affected Mozilla products (Firefox < 55, Firefox ESR < 52.3, Thunderbird < 52.3) to patched versions on Windows systems. Other operating systems are not affected.

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:< 52.3.0< 55.0
ThunderbirdApplication
Affected:< 52.3.0

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:3.0/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. Confirm Windows operating system
    Check the OS type - this vulnerability only affects Windows systems. Run 'systeminfo' or check System Properties to verify the OS is Windows.
    Affected if The system is not running Windows (Linux/macOS are not affected)
  2. Check if Mozilla Firefox is installed
    Look for Firefox installation on the system. Check common paths like C:\Program Files\Mozilla Firefox\ or C:\Program Files (x86)\Mozilla Firefox\, or search for firefox.exe using 'where firefox' or File Explorer.
    Affected if Firefox is not installed on the system
  3. Determine Firefox version
    If Firefox is installed, find the version. Right-click firefox.exe, select Properties, then the Details tab to see File Version. Alternatively, from command line: 'dir "C:\Program Files\Mozilla Firefox\firefox.exe"' or '"C:\Program Files\Mozilla Firefox\firefox.exe" -v'
    Affected if Firefox version is less than 55.0 (or less than 52.3.0 for ESR releases)
  4. Check if Mozilla Thunderbird is installed
    Look for Thunderbird installation. Check paths like C:\Program Files\Mozilla Thunderbird\ or C:\Program Files (x86)\Mozilla Thunderbird\, or search for thunderbird.exe.
    Affected if Thunderbird is not installed on the system
  5. Determine Thunderbird version
    If Thunderbird is installed, find the version. Right-click thunderbird.exe, select Properties, then the Details tab to see File Version. Alternatively, use: 'dir "C:\Program Files\Mozilla Thunderbird\thunderbird.exe"'
    Affected if Thunderbird version is less than 52.3.0

The system is affected if running Windows with Firefox version below 55.0 (or below 52.3.0 for ESR) or Thunderbird version below 52.3.0, since the use-after-free vulnerability exists only in these Windows installations.

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 52.3.0 / 55.0 or later
Fixed in 52.3.055.0
Interim mitigation

Update affected Mozilla products (Firefox < 55, Firefox ESR < 52.3, Thunderbird < 52.3) to patched versions on Windows systems. Other operating systems are not affected.

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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-2017-7804 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