FirefoxWeb browser · Mozilla
CVE-2025-55031
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 · uneditedMalicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker's computer into the target account. This vulnerability was fixed in Firefox for iOS 142 and Focus for iOS 142.
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 confidenceA vulnerability in Firefox for iOS allowed malicious web pages to improperly trigger the OS-level FIDO/hybrid passkey authentication flow via WebAuthn APIs. An attacker within Bluetooth range could trick users into authenticating to the attacker's device instead of the intended legitimate service, enabling account takeover.
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
< 142.0
Firefox FocusWeb browser
< 142.0CVSS 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
- 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 checksWork through these to decide whether this CVE applies to you.
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Check Firefox for iOS versionOpen the App Store, search for Firefox, or go to Settings > General > iPhone Storage > Firefox to view the installed version numberAffected if The installed version is earlier than 142.0 (e.g., 141.x, 140.x, etc.)
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Check Firefox Focus for iOS versionOpen the App Store, search for Firefox Focus, or go to Settings > General > iPhone Storage > Firefox Focus to view the installed version numberAffected if The installed version is earlier than 142.0 (e.g., 141.x, 140.x, etc.)
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Confirm which browser is in useIdentify whether Firefox or Firefox Focus for iOS is the primary browser used on the device for authentication to sensitive servicesAffected if The vulnerable browser (< 142.0) is used for web authentication via passkeys or FIDO credentials
You are affected if Firefox for iOS or Firefox Focus for iOS with a version number below 142.0 is installed and used for WebAuthn-based authentication.
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 · scoped142.0
Upgrade to Firefox for iOS 142 or Focus for iOS 142 or later to remediate. Users should avoid using untrusted networks until updated.
Firefox for iOS 142.0, Focus for iOS 142.0
- Open the App Store app on your iOS device
- Search for "Firefox" or "Firefox Focus"
- Tap the Update button next to the app if an update is available, or install the app if not already installed
- Ensure the updated app shows version 142.0 or later
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
- Testing2.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-55031 — 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-2025-55031 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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- 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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