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FirefoxWeb browser · Mozilla

CVE-2022-29909

HIGH · 8.8 CVSS v3.1 Published 2022-12-22
Fix available
A fix is available. Upgrade to 91.9 / 100.0 or later.
See remediation →
95/100
Remediation priority · Urgent
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
Documents in deeply-nested cross-origin browsing contexts could have obtained permissions granted to the top-level origin, bypassing the existing prompt and wrongfully inheriting the top-level permissions. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

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

A permissions bypass vulnerability in Firefox, Firefox ESR, and Thunderbird allowed documents in deeply-nested cross-origin browsing contexts (iframes) to incorrectly inherit permissions granted to the top-level origin, circumventing the normal permission prompt mechanism.

MitigationUpdate affected products to patched versions: Thunderbird to 91.9+, Firefox ESR to 91.9+, or Firefox to 100+. This is a browser-side vulnerability with no web application changes required.

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:< 100.0
Firefox EsrWeb browser
Affected:< 91.9
ThunderbirdApplication
Affected:< 91.9

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
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 checks

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

  1. Check Firefox version
    In Firefox, go to Help > About Firefox, or run 'firefox --version' from command line, or right-click the firefox.exe file and view Properties > Details to see the version
    Affected if Version is below 100.0 (e.g., 99.x or earlier)
  2. Check Firefox ESR version
    In Firefox ESR, go to Help > About Firefox ESR, or run 'firefox --version' from command line, or check the application log file for the ESR version number
    Affected if Version is below 91.9 (e.g., 91.8.x or earlier)
  3. Check Thunderbird version
    In Thunderbird, go to Help > About Thunderbird, or run 'thunderbird --version' from command line, or view the executable properties
    Affected if Version is below 91.9 (e.g., 91.8.x or earlier)
  4. Confirm browser usage context
    Identify if the browser is used to view web pages containing iframes, particularly nested or cross-origin content that may request permissions (geolocation, notifications, camera/mic access)
    Affected if User browses web content with deeply-nested cross-origin iframes AND browser version is vulnerable

You are affected if your installed Firefox is below 100.0, Firefox ESR is below 91.9, or Thunderbird is below 91.9, and you browse web pages with nested cross-origin iframes that request permissions.

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 91.9 / 100.0 or later
Fixed in 91.9100.0
Interim mitigation

Update affected products to patched versions: Thunderbird to 91.9+, Firefox ESR to 91.9+, or Firefox to 100+. This is a browser-side vulnerability with no web application changes required.

Recommended fix High confidence

Firefox 100.0, Firefox ESR 91.9, or Thunderbird 91.9

  1. 1. Check the current installed version of Firefox, Firefox ESR, or Thunderbird
  2. 2. For Firefox: Navigate to Menu > Help > About Firefox to check the current version
  3. 3. For Thunderbird: Navigate to Menu > Help > About Thunderbird to check the current version
  4. 4. If the installed version is below 100.0 (Firefox) or 91.9 (ESR/Thunderbird), download the updated version from the official Mozilla website at www.mozilla.org
  5. 5. Close all instances of the browser/application
  6. 6. Run the installer for the new version
  7. 7. Restart the application after installation completes
  8. 8. Verify the installed version matches or exceeds the fixed release (Firefox >= 100.0, Firefox ESR >= 91.9, Thunderbird >= 91.9)
Caveat Major version upgrades (e.g., Firefox 91 to 100) may occasionally cause compatibility issues with older extensions or themes; however, the high-severity security vulnerability warrants immediate upgrade

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
3.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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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-2022-29909 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