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FirefoxWeb browser · Mozilla

CVE-2023-32206

MEDIUM · 6.5 CVSS v3.1 Published 2023-06-02
Fix available
A fix is available. Upgrade to 102.11 / 113.0 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

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
An out-of-bound read could have led to a crash in the RLBox Expat driver. This vulnerability affects Firefox < 113, Firefox ESR < 102.11, and Thunderbird < 102.11.

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

An out-of-bounds read vulnerability in the RLBox sandboxed Expat XML parser library in Firefox and Thunderbird could allow a remote attacker to crash the affected application via specially crafted XML content.

MitigationUpdate to Firefox 113 or later, Firefox ESR 102.11 or later, or Thunderbird 102.11 or later to obtain the vendor patch.

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:< 113.0
Firefox EsrWeb browser
Affected:< 102.11
ThunderbirdApplication
Affected:< 102.11

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
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 checks

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

  1. Identify installed Mozilla product
    Check if Firefox or Thunderbird is installed on the system. On Windows, look in Program Files or Program Files (x86). On macOS, check /Applications. On Linux, check package manager or common install paths.
    Affected if Any of Firefox, Firefox ESR, or Thunderbird is installed
  2. Determine Firefox version
    Open Firefox, go to Menu > Help > About Firefox (or navigate to about:support). Note the version number displayed.
    Affected if Version is less than 113.0 (or any ESR version less than 102.11)
  3. Determine Thunderbird version
    Open Thunderbird, go to Menu > Help > About Thunderbird (or navigate to about:support). Note the version number displayed.
    Affected if Version is less than 102.11
  4. Confirm the RLBox Expat module is active
    This vulnerability is in the RLBox sandboxed Expat XML parser. By default, Firefox and Thunderbird use this component for XML parsing. No manual configuration check is required - the vulnerable code path is triggered when processing specially crafted XML content.
    Affected if The browser or mail client processes XML content (which occurs during normal web browsing and email handling)

The environment is affected if Firefox version is below 113.0, Firefox ESR is below 102.11, or Thunderbird is below 102.11, and the application processes XML content.

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 102.11 / 113.0 or later
Fixed in 102.11113.0
Interim mitigation

Update to Firefox 113 or later, Firefox ESR 102.11 or later, or Thunderbird 102.11 or later to obtain the vendor patch.

Recommended fix High confidence

Firefox 113.0, Firefox ESR 102.11, or Thunderbird 102.11

  1. Back up important data such as bookmarks, passwords, and email settings before upgrading
  2. Open Firefox or Thunderbird and navigate to Help > About (or on macOS Firefox > About Firefox / Thunderbird > About Thunderbird)
  3. Click 'Check for Updates' or allow the application to check for updates automatically
  4. Download and install the latest version when prompted, or manually download from the official Mozilla website (www.mozilla.org) if automatic update fails
  5. Restart the application after the update completes
  6. Verify the update was successful by checking the version number in About (Firefox 113.0+, Firefox ESR 102.11+, or Thunderbird 102.11+)
Caveat Standard minor version upgrades typically have no breaking changes; ensure third-party extensions are compatible with the new version

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation0.5 h
  • Testing0.5 h
  • Review / QA0.5 h
2.5 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-2023-32206 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