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FirefoxWeb browser · Mozilla

CVE-2023-4576

HIGH · 8.6 CVSS v3.1 Published 2023-09-11
Fix available
A fix is available. Upgrade to 102.15 / 115.2 or later.
See remediation →
95/100
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
On Windows, an integer overflow could occur in `RecordedSourceSurfaceCreation` which resulted in a heap buffer overflow potentially leaking sensitive data that could have led to a sandbox escape. *This bug only affects Firefox on Windows. Other operating systems are unaffected.* This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.

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

Integer overflow in RecordedSourceSurfaceCreation on Windows causes heap buffer overflow in Firefox/Thunderbird, potentially leaking sensitive data and enabling sandbox escape.

MitigationUpdate Firefox to >=117, Firefox ESR to >=102.15 or >=115.2, and Thunderbird to >=102.15 or >=115.2. This is a client-side vulnerability; apply vendor patches.

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:< 117.0>= 115.0, < 115.2
Firefox EsrWeb browser
Affected:< 102.15
ThunderbirdApplication
Affected:< 115.2

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
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

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. Confirm Windows platform
    Verify the operating system is Windows (this vulnerability only affects Windows builds)
    Affected if Running on Windows with a vulnerable Firefox or Thunderbird version
  2. Check Firefox version
    Open Firefox, navigate to Menu > Help > About Firefox, or enter 'about:support' in the address bar to view the version number
    Affected if Firefox version is 115.0 through 115.1.x, or below 102.15 for ESR versions
  3. Check Thunderbird version
    Open Thunderbird, navigate to Menu > Help > About Thunderbird to view the version number
    Affected if Thunderbird version is below 115.2 (or below 102.15 for ESR-like versions)
  4. Identify graphics recording functionality
    Inspect running processes or check for usage of features that involve surface/canvas recording (such as screenshot tools, screen capture extensions, or canvas recording APIs in WebGL content)
    Affected if The RecordedSourceSurfaceCreation code path is actively being used on a vulnerable version

You are affected if running Windows with Firefox < 117, Firefox ESR < 102.15, or Thunderbird < 115.2, and the vulnerable graphics recording code path is exercised.

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 102.15 / 115.2 / 117.0 or later
Fixed in 102.15115.2117.0
Interim mitigation

Update Firefox to >=117, Firefox ESR to >=102.15 or >=115.2, and Thunderbird to >=102.15 or >=115.2. This is a client-side vulnerability; apply vendor patches.

Recommended fix High confidence

Firefox 117.0+; Firefox ESR 102.15+ (or latest ESR); Thunderbird 115.2+

  1. For Firefox on Windows users: Upgrade to Firefox 117.0 or later by going to Help > About Firefox > Check for Updates, or download from https://www.mozilla.org/firefox/
  2. For Firefox ESR on Windows users: Upgrade to Firefox ESR 102.15 or later (or the latest ESR 115.x release), or download from https://www.mozilla.org/firefox/enterprise/
  3. For Thunderbird on Windows users: Upgrade to Thunderbird 115.2 or later by going to Help > About Thunderbird > Check for Updates, or download from https://www.thunderbird.net/
  4. After upgrading, restart the application to complete the update
Caveat None expected - this is a security patch upgrade. Minor version upgrades typically retain user settings and extensions.

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
4.0 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

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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-2023-4576 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