FirefoxWeb browser · Mozilla
CVE-2025-14326
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 · uneditedUse-after-free in the Audio/Video: GMP component. This vulnerability was fixed in Firefox 146 and Thunderbird 146.
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 use-after-free vulnerability exists in the GMP (Gecko Media Plugins) component of Firefox and Thunderbird, allowing an attacker to potentially execute arbitrary code by accessing freed memory. The critical CVSS 9.8 score indicates this flaw is exploitable remotely without authentication and provides complete system compromise.
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
< 146.0< 146.0CVSS 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 versionNavigate to Firefox menu > Help > About Firefox, or enter 'about:support' in the address bar, or run 'firefox --version' from command lineAffected if The displayed version is below 146.0 (e.g., 145.x, 144.x, etc.)
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Check Thunderbird versionNavigate to Thunderbird menu > Help > About Thunderbird, or enter 'about:support' in the address bar, or run 'thunderbird --version' from command lineAffected if The displayed version is below 146.0 (e.g., 145.x, 144.x, etc.)
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Verify GMP plugin usageIn Firefox, navigate to 'about:addons' and click on Plugins section; look for any Gecko Media Plugins (such as Adobe Flash or other third-party media plugins) that are installed and enabledAffected if Any GMP-type media plugin is installed and enabled in the browser
If either Firefox or Thunderbird is installed with a version below 146.0 and has GMP plugins enabled, the environment is vulnerable to this use-after-free flaw.
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 · scoped146.0
Upgrade to Firefox 146, Thunderbird 146, or later versions to remediate this vulnerability. No workarounds are available for this client-side flaw.
Firefox 146.0 and Thunderbird 146.0
- Check current Firefox version by navigating to about:firefox or Help > About Firefox
- Check current Thunderbird version by navigating to Help > About Thunderbird
- Download Firefox 146.0 from the official Mozilla website (www.mozilla.org)
- Download Thunderbird 146.0 from the official Mozilla website (www.mozilla.org)
- Close all instances of Firefox and Thunderbird
- Run the Firefox 146.0 installer and complete the upgrade
- Run the Thunderbird 146.0 installer and complete the upgrade
- Restart both applications and verify the version is now 146.0
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 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 $1,696.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-14326 — 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-2025-14326 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