dbcve.org
FirefoxWeb browser · Mozilla

CVE-2023-6211

MEDIUM · 6.5 CVSS v3.1 Published 2023-11-21
Fix available
A fix is available. Upgrade to 120.0 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

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
If an attacker needed a user to load an insecure http: page and knew that user had enabled HTTPS-only mode, the attacker could have tricked the user into clicking to grant an HTTPS-only exception if they could get the user to participate in a clicking game. This vulnerability affects Firefox < 120.

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 confidence

Firefox's HTTPS-only mode security feature can be bypassed by tricking users into a clicking game that exploits the exception-granting mechanism, allowing attackers to force users to load insecure http: pages despite having HTTPS-only mode enabled.

MitigationUpgrade Firefox to version 120 or later to obtain the patch for this vulnerability.

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
Affected:< 120.0

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
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Firefox version number
    Navigate to Firefox menu > Help > About Firefox, or enter 'about:support' in the address bar to view the version number
    Affected if Version is lower than 120.0 (e.g., 119.x, 118.x, etc.)
  2. Verify HTTPS-only mode is enabled
    Navigate to Firefox menu > Settings > Privacy & Security, scroll to 'HTTPS-Only Mode' section and confirm the toggle is set to 'Enabled' or 'Enabled in all windows'
    Affected if HTTPS-only mode is enabled and the Firefox version is below 120.0
  3. Confirm user is not exposed to social engineering
    Review browser activity logs or network traffic to detect any automated clicking games, scripted exception prompts, or unusual pop-up sequences that may trick users into granting exceptions to HTTPS-only mode
    Affected if Users have been exposed to malicious pages that exploit the exception-granting mechanism to bypass HTTPS-only protection

A user is affected if they are running Firefox versions below 120.0 with HTTPS-only mode enabled and have been socially engineered into a clicking scenario that exploits the exception mechanism.

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.

dbcve · scoped
Upgrade available Upgrade to 120.0 or later
Fixed in 120.0
Interim mitigation

Upgrade Firefox to version 120 or later to obtain the patch for this vulnerability.

Recommended fix High confidence

Firefox 120.0

  1. Upgrade Firefox to version 120.0 or later

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-6211 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2023-6211 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
  • No spam, self-promotion, credentials, or personal data