FirefoxWeb browser · Mozilla
CVE-2023-4573
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 · uneditedWhen receiving rendering data over IPC `mStream` could have been destroyed when initialized, which could have led to a use-after-free causing a potentially exploitable crash. 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 confidenceUse-after-free vulnerability in Firefox and Thunderbird's IPC rendering code. When receiving rendering data over IPC, the mStream object could be destroyed during initialization, leading to a dangling pointer that is later accessed, causing a potentially exploitable crash.
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
< 117.0>= 115.0, < 115.2
Firefox EsrWeb browser
< 102.15< 115.2CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/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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Identify installed Mozilla productCheck if Firefox or Thunderbird is installed and note the product nameAffected if Product is Firefox or Thunderbird (this CVE does not affect other Mozilla products)
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Determine Firefox version (regular edition)Open Firefox, go to Menu > Help > About Firefox; or run firefox --versionAffected if Version is 115.0 through 115.1.x, or any version below 117.0 (115.x range versions below 115.2 are vulnerable)
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Determine Firefox ESR versionOpen Firefox ESR, go to Menu > Help > About Firefox ESR; or run firefox --versionAffected if Version is below 102.15 (all versions before 102.15 are vulnerable)
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Determine Thunderbird versionOpen Thunderbird, go to Menu > Help > About Thunderbird; or run thunderbird --versionAffected if Version is below 115.2 (all versions before 115.2 are vulnerable)
You are affected if you are running Firefox (any 115.0-115.1.x or below 117.0), Firefox ESR (below 102.15), or Thunderbird (below 115.2).
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 · scoped102.15115.2117.0
Upgrade to Firefox 117+, Firefox ESR 102.15+/115.2+, or Thunderbird 102.15+/115.2+ to patch the vulnerability.
Firefox 117.0+ (or ESR 102.15+/115.2+); Thunderbird 102.15+/115.2+
- 1. Identify the installed Firefox, Firefox ESR, or Thunderbird version by navigating to Help > About (or checking application preferences)
- 2. For Firefox users: Upgrade to version 117.0 or later
- 3. For Firefox ESR 102.x users: Upgrade to version 102.15 or later
- 4. For Firefox ESR 115.x users: Upgrade to version 115.2 or later
- 5. For Thunderbird 102.x users: Upgrade to version 102.15 or later
- 6. For Thunderbird 115.x users: Upgrade to version 115.2 or later
- 7. Restart the application 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
- Implementation2.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-4573 — 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-2023-4573 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