FirefoxWeb browser · Mozilla

CVE-2026-2792

CRITICAL · 9.8 CVSS v3.1 Published 2026-02-24

Fix available

A fix is available. Upgrade to 140.8.0 / 148.0 or later.

See remediation →

100/100

Remediation priority · Urgent

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

Memory safety bugs present in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Technical summary

dbcve analysis · high confidence

Memory safety bugs in Firefox ESR 140.7, Firefox 147, Thunderbird ESR 140.7, and Thunderbird 147 allowed evidence of memory corruption that could be exploited for arbitrary code execution.

MitigationUpdate affected installations to Firefox 148, Firefox ESR 140.8, Thunderbird 148, or Thunderbird 140.8 to patch the memory corruption vulnerabilities.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

FirefoxWeb browser

Affected:< 140.8.0< 148.0

ThunderbirdApplication

Affected:< 140.8.0< 148.0

CVSS breakdown

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?

dbcve checks

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

Identify installed Mozilla product

Open the application and go to Help > About (or on macOS, Firefox/Thunderbird menu > About). The product name (Firefox or Thunderbird) and version number will be displayed.

Affected if The product is Firefox or Thunderbird
Determine if running ESR version

In the About window, look for 'ESR' or 'Extended Support Release' in the version string. If present, it's an ESR release; otherwise, it's a standard release.

Affected if Version string contains 'ESR'
Compare version against affected ranges

Note the full version number from the About screen. Compare: if ESR, check if version is < 140.8.0; if standard, check if version is < 148.0

Affected if Firefox or Thunderbird version is below 140.8.0 (ESR) or below 148.0 (non-ESR)

The environment is affected if Firefox or Thunderbird is installed with a version less than 140.8.0 (ESR releases) or less than 148.0 (standard releases).

Generated from the published advisory. Verify against your own configuration.

Remediation

dbcve · scoped

Upgrade available Upgrade to 140.8.0 / 148.0 or later

Fixed in 140.8.0148.0

Interim mitigation

Update affected installations to Firefox 148, Firefox ESR 140.8, Thunderbird 148, or Thunderbird 140.8 to patch the memory corruption vulnerabilities.

Recommended fix High confidence

Firefox 148, Firefox ESR 140.8.0+, Thunderbird 148, or Thunderbird ESR 140.8.0+

Check current Firefox or Thunderbird version by navigating to Help > About (or using the menu)
Download Firefox 148 or later from the official Mozilla website (www.mozilla.org)
Download Thunderbird 148 or later from the official Mozilla website (www.mozilla.org)
Alternatively, for ESR users, download Firefox ESR 140.8.0 or later / Thunderbird ESR 140.8.0 or later
Install the downloaded installer and restart the application
Verify the version by checking Help > About to confirm the update was applied

Caveat Standard Mozilla security updates typically do not introduce breaking changes; this is a routine upgrade to a newer stable or ESR release

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

Fix this in Firefox Scoped from the published advisory

Consultation2.0 h
Implementation4.0 h
Testing2.0 h
Review / QA1.0 h

9.0 hours of engineering $1,600

Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

Free · runs locally

dbcve dependency scanner

Check whether your project pulls in CVE-2026-2792 — 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

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-2792 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2026-2792?

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.

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

At a glance

A fix existsUpgrade to 140.8.0 / 148.0 or later

Severity 9.8 Critical

Exploit likelihood EPSS, next 30 days 0.3%

Affects: Firefox

Remediation

A high-priority fix

Fix this in Firefox 9 hrs · Low

Typical engagement from $1,600

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2026-2792 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References