FirefoxWeb browser · Mozilla
CVE-2017-7768
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 · uneditedThe Mozilla Maintenance Service can be invoked by an unprivileged user to read 32 bytes of any arbitrary file on the local system by convincing the service that it is reading a status file provided by the Mozilla Windows Updater. The Mozilla Maintenance Service executes with privileged access, bypassing system protections against unprivileged users. Note: This attack requires local system access and only affects Windows. Other operating systems are not affected. This vulnerability affects Firefox ESR < 52.2 and Firefox < 54.
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 confidenceThe Mozilla Maintenance Service on Windows executes with elevated privileges and can be tricked by an unprivileged user into reading 32 bytes from any arbitrary local file by masquerading the target file as a Mozilla Windows Updater status file, enabling local privilege escalation through arbitrary file read.
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
< 52.2.0< 54.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Firefox versionOpen Windows Registry Editor and navigate to HKLM\SOFTWARE\Mozilla\Mozilla Firefox\CurrentVersion, or check the version property of firefox.exe in the Firefox installation directory (typically C:\Program Files\Mozilla Firefox\firefox.exe)Affected if The version is less than 52.2.0 or between 52.2.0 and 53.x (i.e., < 54.0)
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Verify Mozilla Maintenance Service existsOpen Services.msc and look for 'Mozilla Maintenance Service', or run 'sc query' in Command Prompt to list services and filter for 'Mozilla Maintenance'Affected if The service exists on the system (the vulnerability requires this service to be present)
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Confirm service runs with elevated privilegesIn Services.msc, right-click Mozilla Maintenance Service and select Properties, then note the 'Log On' account (typically Local System or a service account with elevated privileges)Affected if The service runs under Local System, Local Service, or another privileged account
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Check for user write access to Firefox directoriesAttempt to create a test file in the Firefox program directory (C:\Program Files\Mozilla Firefox\) or the updater directory within AppData. If creation fails with access denied, the directory is likely protected.Affected if An unprivileged user can write to directories where the Maintenance Service looks for updater status files, enabling the attack vector
A user is affected if they run Firefox versions below 54.0 on Windows with the Mozilla Maintenance Service installed and running with elevated privileges, and an unprivileged attacker can write to locations where the service searches for status files.
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 data52.2.054.0
Upgrade to Firefox 54+, Firefox ESR 52.2+, or later versions to remediate the vulnerable Mozilla Maintenance Service behavior.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 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 $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-7768 — 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-2017-7768 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
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