FirefoxWeb browser · Mozilla
CVE-2021-29973
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 · uneditedPassword autofill was enabled without user interaction on insecure websites on Firefox for Android. This was corrected to require user interaction with the page before a user's password would be entered by the browser's autofill functionality *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 90.
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 confidenceFirefox for Android versions before 90 would automatically fill saved passwords into web forms without requiring any user interaction, even on insecure (non-HTTPS) websites. This allowed attackers on the same network to potentially intercept credentials by injecting malicious content into unprotected HTTP pages.
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
< 90.0CVSS 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
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.
-
Check Firefox for Android versionOpen Firefox for Android, tap the three-dot menu, go to Settings > About Firefox. Note the version number displayed.Affected if Version is below 90.0 (e.g., 89.x, 88.x, etc.)
-
Verify password autofill is enabledGo to Firefox for Android Settings > Privacy & Security > Logins and Passwords. Check if 'Autofill logins' toggle is turned ON.Affected if Autofill logins is enabled (toggle is ON)
A user is affected if they are running Firefox for Android version below 90.0 AND have password autofill enabled, as credentials will automatically fill on insecure HTTP websites without interaction.
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 · scoped90.0
Update Firefox for Android to version 90 or later. Until the update is applied, users should disable password autofill in Firefox settings and avoid autofill on any website accessed over HTTP.
Firefox 90.0 for Android (or current latest stable release)
- Open Google Play Store on your Android device
- Search for "Firefox" or "Firefox for Android"
- Tap on the Firefox app
- If an update is available, tap "Update" to install Firefox 90.0 or later
- Alternatively, enable automatic updates in the Play Store to receive future security updates automatically
- Verify the installed version by going to Firefox Menu > Settings > About Firefox - it should show version 90.0 or higher
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 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-2021-29973 — 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-2021-29973 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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