dbcve.org
FirefoxWeb browser · Mozilla

CVE-2023-4056

CRITICAL · 9.8 CVSS v3.1 Published 2023-08-01
Fix available
A fix is available. Upgrade to 102.14 / 115.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Memory safety bugs present in Firefox 115, Firefox ESR 115.0, Firefox ESR 102.13, Thunderbird 115.0, and Thunderbird 102.13. 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 affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

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

Memory safety bugs in Firefox and Thunderbird versions before 116 (Firefox), 102.14 (Firefox ESR), and 115.1 (Firefox ESR) allow remote attackers to potentially execute arbitrary code via memory corruption.

MitigationUpgrade to Firefox 116+, Firefox ESR 102.14+, or Firefox ESR 115.1+ to patch the memory safety vulnerabilities.

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:< 116.0>= 102.0, < 102.14>= 115.0, < 115.1
Debian LinuxOperating system
Affected:= 10.0= 11.0= 12.0

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
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 checks

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

  1. Check Firefox version in the application
    Open Firefox and navigate to Help > About Firefox (or go to about:support in the address bar). The version number is displayed at the top.
    Affected if The displayed version is less than 116.0 (for regular Firefox), or is between 102.0 and 102.13.x inclusive, or between 115.0 and 115.0.x inclusive (for Firefox ESR).
  2. Check Firefox ESR version via command line
    Run 'firefox --version' or 'firefox-esr --version' in a terminal to see the installed version and whether it is the ESR (Extended Support Release) variant.
    Affected if The version shown is 102.0 through 102.13, or 115.0 through 115.0.x, indicating an unpatched ESR release.
  3. Check Thunderbird version if installed
    Open Thunderbird and go to Help > About Thunderbird (or navigate to about:support). Note the version number displayed.
    Affected if Thunderbird is installed and its version is below the corresponding patched release for the same codebase (verify against Mozilla's Thunderbird release notes for version 115.1 or later).
  4. Verify installed package version on Debian systems
    On Debian-based systems, run 'dpkg -l | grep firefox' or 'apt policy firefox-esr' to see the installed package version from the system package manager.
    Affected if The installed package version corresponds to an unpatched release (check against the affected version ranges for the specific Debian version in use).

You are affected if Firefox, Firefox ESR, or Thunderbird is installed and its version falls below the patched releases (116.0 for Firefox, 102.14 or 115.1 for ESR, or their equivalent for Thunderbird).

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 102.14 / 115.1 / 116.0 or later
Fixed in 102.14115.1116.0
Interim mitigation

Upgrade to Firefox 116+, Firefox ESR 102.14+, or Firefox ESR 115.1+ to patch the memory safety vulnerabilities.

Recommended fix High confidence

Firefox 116.0, Firefox ESR 102.14, or Firefox ESR 115.1 (depending on your release channel)

  1. Open Firefox and navigate to Menu > Help > About Firefox to check current version
  2. If using Debian, run: sudo apt update && sudo apt install firefox (or firefox-esr for ESR version)
  3. Alternatively, download Firefox 116.0 or later from https://www.mozilla.org/en-US/firefox/
  4. For ESR users: Upgrade to Firefox ESR 102.14 or Firefox ESR 115.1 depending on your release track
  5. Restart the browser after 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
  • Implementation1.0 h
  • Testing0.5 h
  • Review / QA0.5 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.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-4056 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-4056 in production — separate from our analysis above.

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