FirefoxWeb browser · Mozilla
CVE-2015-4498
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 add-on installation feature in Mozilla Firefox before 40.0.3 and Firefox ESR 38.x before 38.2.1 allows remote attackers to bypass an intended user-confirmation requirement by constructing a crafted data: URL and triggering navigation to an arbitrary http: or https: URL at a certain early point in the installation process.
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 confidenceMozilla Firefox contains a vulnerability in its add-on installation feature where a crafted data: URL can be used to bypass user confirmation requirements during add-on installation. By triggering navigation to an arbitrary http: or https: URL at a specific early point in the installation process, remote attackers can install add-ons without user consent.
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
<= 40.0.2= 38.0= 38.0.1= 38.0.5= 38.1.0= 38.2.0CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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 Firefox version numberOpen Firefox, click the menu button (three horizontal lines), select Help, then About Firefox. The version number is displayed at the top of the window.Affected if The displayed version is 40.0.2 or lower, or exactly 38.0, 38.0.1, 38.0.5, 38.1.0, or 38.2.0
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Confirm ESR version if applicableIf running Firefox ESR, verify the exact ESR version number in the same About dialog. ESR versions are labeled as such (e.g., Firefox ESR 38.x).Affected if The ESR version is 38.2.0 or earlier
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Verify add-on installation behavior is unchangedThis CVE involves bypassing add-on installation confirmation dialogs. Without attempting exploitation, no simple config check exists; version-based detection is the primary method.Affected if Unable to verify through configuration alone - version check in step 1 is definitive
If Firefox version is 40.0.2 or lower, or exactly 38.0/38.0.1/38.0.5/38.1.0/38.2.0 (or ESR 38.2.0 or earlier), the add-on installation bypass vulnerability is present.
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 dataUpdate Mozilla Firefox to version 40.0.3 or later (or Firefox ESR 38.2.1 or later) to patch this vulnerability. Users should not install add-ons from untrusted sources and should confirm browser updates are applied promptly.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 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 $1,456.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-4498 — 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-2015-4498 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
- No spam, self-promotion, credentials, or personal data