FirefoxWeb browser · Mozilla
CVE-2025-11720
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 Firefox and Firefox Focus UI for the Android custom tab feature only showed the "site" that was loaded, not the full hostname. User supplied content hosted on a subdomain of a site could have been used to fool a user into thinking it was content from a different subdomain of that site. This vulnerability was fixed in Firefox 144.
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 confidenceThis is a UI spoofing vulnerability in Firefox and Firefox Focus for Android where the custom tab feature only displayed the base site name instead of the full hostname. This allowed malicious content hosted on subdomains to appear as if it came from a different, potentially trusted subdomain, enabling phishing attacks.
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
< 144.0CVSS 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
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/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 checksWork through these to decide whether this CVE applies to you.
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Check Firefox desktop versionOpen Firefox, click the menu button (three horizontal lines), select Help, then About Firefox. The version number is displayed on the page that opens.Affected if The displayed version number is less than 144.0 (for example, 143.5, 143.0, 142.x, etc.)
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Check Firefox Focus for Android versionOpen the Google Play Store app, search for Firefox Focus, or go to your installed apps list. Tap on Firefox Focus to view its version information, or open Firefox Focus and navigate to Settings > About.Affected if The displayed version number is less than 144.0 (for example, 143.5, 143.0, 142.x, etc.)
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Identify if Custom Tabs feature is in useCustom Tabs are used when you click a link in an external app (such as email, messaging, or another application) that opens in a browser-like interface within that app rather than launching the full Firefox browser.Affected if You use apps that open links in Custom Tabs and your Firefox or Firefox Focus version is below 144.0
You are affected if you are running any version of Firefox or Firefox Focus for Android below 144.0 and use the Custom Tabs feature to open links from external applications.
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.
dbcve · scoped144.0
Upgrade Firefox and Firefox Focus for Android to version 144 or later to obtain the fix that displays the full hostname in the custom tab UI.
Firefox 144.0 (or later) for Android
- Open the Google Play Store app on your Android device
- Search for "Firefox" or "Mozilla Firefox"
- Tap the "Update" button if an update is available
- Alternatively, navigate to Settings > Apps > Firefox > Update (or check for updates within the app)
- Verify the updated version is 144.0 or later by going to the Firefox menu > Help > About Firefox
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-11720 — 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-2025-11720 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