FirefoxWeb browser · Mozilla
CVE-2023-23605
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 · uneditedMozilla developers and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 108 and Firefox ESR 102.6. 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 < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.
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 · moderate confidenceMemory safety vulnerabilities in Firefox and Thunderbird that allow memory corruption. The bugs in the browser's rendering and JavaScript engines could potentially be exploited to achieve arbitrary code execution with sufficient effort.
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
< 109.0
Firefox EsrWeb browser
< 102.7< 102.7CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Firefox versionOn Windows, go to Help > About Firefox. On macOS, go to Firefox > About Firefox. On Linux, run: firefox --versionAffected if Version is less than 109.0 for standard Firefox
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Identify installed Firefox ESR versionOn Windows, go to Help > About Firefox ESR. On macOS, go to Firefox ESR > About Firefox ESR. On Linux, run: firefox-esr --versionAffected if Version is less than 102.7 for Firefox ESR
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Identify installed Thunderbird versionOn Windows, go to Help > About Thunderbird. On macOS, go to Thunderbird > About Thunderbird. On Linux, run: thunderbird --versionAffected if Version is less than 102.7 for Thunderbird
You are affected if any installed Firefox version is below 109.0, or any Firefox ESR or Thunderbird version is below 102.7.
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 · scoped102.7109.0
Update to Firefox 109, Firefox ESR 102.7, or Thunderbird 102.7 to patch the memory safety vulnerabilities.
Firefox 109.0, Firefox ESR 102.7, or Thunderbird 102.7 (or later)
- Back up your Firefox/Thunderbird profile data (bookmarks, passwords, extensions, and other settings) to prevent data loss
- Close all running instances of Firefox, Firefox ESR, or Thunderbird
- Download the appropriate fixed version from the official Mozilla website (www.mozilla.org) or update via your system's package manager
- For Firefox: Install version 109.0 or later
- For Firefox ESR: Install version 102.7 or later
- For Thunderbird: Install version 102.7 or later
- Restart the application after installation
- Verify the installed version by checking Help > About Firefox/Thunderbird
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
- 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-23605 — 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-2023-23605 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