MozillaApplication

CVE-2007-4039

CRITICAL · 9.8 CVSS v3.1 Published 2007-07-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Argument injection vulnerability involving Mozilla, when certain URIs are registered, allows remote attackers to conduct cross-browser scripting attacks and execute arbitrary commands via shell metacharacters in an unspecified URI, which are inserted into the command line when invoking the handling process, a similar issue to CVE-2007-3670.

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 confidence

Argument injection vulnerability in Mozilla's URI handling mechanism allows remote attackers to inject shell metacharacters into URIs that get passed to the command line when invoking registered URI handlers, enabling arbitrary command execution. This affects how certain custom URIs are processed when registered with the browser.

MitigationUpdate Mozilla Firefox to the latest patched version and review/disable any untrusted or unnecessary URI protocol handlers registered in the browser.

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
MozillaApplication
Affected:all versions

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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. Identify installed Mozilla product and version
    Check Help > About or run 'mozilla -version' / 'firefox -v' from command line
    Affected if The installed version is any release of Mozilla Firefox or Mozilla Suite (the vulnerability affects all versions)
  2. Check for registered URI protocol handlers
    Navigate to about:config in Firefox and search for 'protocol.handler' preferences. Also check Extensions for any that register custom URI schemes
    Affected if Any custom or third-party protocol handlers are registered (e.g., myapp://, custom://, etc.)
  3. Inspect protocol handler command configurations
    In about:config, locate entries under protocol.handler.exposed.* and protocol.handler.service.* to see which applications are invoked and what command templates are used
    Affected if Any registered handler points to an executable or includes user-controllable arguments in its command template
  4. Review recently installed extensions
    Check Tools > Add-ons > Extensions for any that add custom protocol handlers, particularly untrusted or unused ones
    Affected if An extension that registers a protocol handler is installed and enabled

If any untrusted, unnecessary, or compromised custom URI protocol handlers are registered in the browser, the environment is vulnerable to argument injection via malicious web pages.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Mozilla Firefox to the latest patched version and review/disable any untrusted or unnecessary URI protocol handlers registered in the browser.

Fix this in Mozilla Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2007-4039 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2007-4039 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
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