FirefoxWeb browser · Mozilla
CVE-2026-16412
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 · uneditedMemory safety bugs present in Firefox ESR 140.12 and Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
In the news
Third-party coverageSurfaced from public web coverage — external links open in a new tab.
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 · moderate confidenceMemory safety bugs in Firefox ESR 140.12 and Firefox 152 (and corresponding Thunderbird versions) allowed memory corruption that could be exploited for arbitrary code execution. This is a classic memory safety vulnerability class (likely use-after-free, heap buffer overflow, or similar) in the browser/email client codebase.
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
< 153.0.0>= 140.1.0, < 140.13.0CVSS 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 installed Firefox versionNavigate to Firefox menu > Help > About Firefox, or enter 'about:support' in the address bar to view the version numberAffected if Version is 140.1.0 through 140.12.x, or any version below 153.0.0 (such as 151.x or 152.x)
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Confirm Firefox edition and buildIn 'about:support' page, check the 'Application Basics' section for the version and build identifierAffected if Version matches the affected ranges above and the build is from the main release channel
If your Firefox installation shows a version between 140.1.0 and 140.12.x inclusive, or any version lower than 153.0.0, you are running an affected version and should verify the patch status with your organization or update to Firefox 153 or later.
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 · scoped140.13.0153.0.0
Upgrade immediately to Firefox 153, Firefox ESR 140.13, Thunderbird 153, or Thunderbird 140.13 or later to remediate the memory corruption vulnerabilities.
Firefox 153 (standard) or Firefox ESR 140.13 (ESR)
- 1. Check the current Firefox version by navigating to Menu > Help > About Firefox
- 2. If running Firefox 152 or earlier, download Firefox 153 from the official Mozilla website (www.mozilla.org)
- 3. If running Firefox ESR 140.12 or earlier, download Firefox ESR 140.13 from the official Mozilla website
- 4. Close all Firefox windows and instances
- 5. Run the installer and follow the prompts to complete the upgrade
- 6. Restart Firefox and verify the version in Menu > Help > About Firefox shows either 153 or ESR 140.13
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-16412 — 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-2026-16412 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