FirefoxWeb browser · Mozilla
CVE-2023-29535
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 · uneditedFollowing a Garbage Collector compaction, weak maps may have been accessed before they were correctly traced. This resulted in memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 112, Focus for Android < 112, Firefox ESR < 102.10, Firefox for Android < 112, and Thunderbird < 102.10.
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 confidenceA race condition in Firefox's JavaScript Garbage Collector allows weak maps to be accessed before proper tracing completes during compaction, leading to memory corruption and potentially exploitable crashes.
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
< 112.0
Firefox EsrWeb browser
< 102.10
Firefox MobileWeb browser
< 112.0< 112.0< 102.10CVSS 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 which Mozilla application is installed by looking for executable files: Firefox typically in program directories, Thunderbird in email clients, or Focus on Android devices. On desktop, you can check About menu or run 'firefox --version', 'thunderbird --version', or check the application binary.Affected if Any of Firefox, Firefox ESR, Thunderbird, or Focus for Android is installed
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Determine installed version numberOpen the application and navigate to Help > About, or use command line: 'firefox --version', 'firefox-esr --version', or 'thunderbird --version'. On Android, check Settings > Apps > Focus > Version.Affected if Version is less than 112.0 for Firefox/Focus, or less than 102.10 for Firefox ESR/Thunderbird
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Compare against affected version rangesCompare your discovered version number against the affected ranges: Firefox < 112.0, Firefox ESR < 102.10, Thunderbird < 102.10, Focus < 112.0.Affected if Installed version falls within any of these ranges: Firefox < 112.0, Firefox ESR < 102.10, Thunderbird < 102.10, Focus < 112.0
If any Mozilla product (Firefox, Firefox ESR, Thunderbird, or Focus) is installed with a version below 112.0 (or below 102.10 for ESR/Thunderbird), the environment is affected by this GC race condition vulnerability.
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 · scoped102.10112.0
Update all affected Firefox, Firefox ESR, Thunderbird, and Focus for Android installations to version 112 (or 102.10 for ESR/Thunderbird) or later to patch the GC compaction vulnerability.
Firefox 112.0, Firefox ESR 102.10, Focus 112.0, Thunderbird 102.10
- For Firefox users: Upgrade to Firefox 112.0 or later by navigating to Help > About Firefox > Check for Updates
- For Firefox ESR users: Upgrade to Firefox ESR 102.10 or later
- For Thunderbird users: Upgrade to Thunderbird 102.10 or later
- For Focus for Android users: Upgrade to Focus 112.0 or later
- After upgrading, verify the version by checking Help > About to confirm the installed version matches or exceeds the fixed release
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
- Testing1.0 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 $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-29535 — 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-2023-29535 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