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FirefoxWeb browser · Mozilla

CVE-2023-29548

MEDIUM · 6.5 CVSS v3.1 Published 2023-06-02
Fix available
A fix is available. Upgrade to 102.10 / 112.0 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
A wrong lowering instruction in the ARM64 Ion compiler resulted in a wrong optimization result. 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 confidence

A logic error in the ARM64 Ion JavaScript JIT compiler causes incorrect lowering instructions, resulting in wrong optimization results. This compiler bug can produce unexpected behavior in JavaScript execution on 64-bit ARM devices, potentially leading to memory corruption or incorrect computation if exploited.

MitigationUpdate affected Mozilla products (Firefox, Firefox ESR, Thunderbird, Focus for Android) to versions 112 or later (or 102.10 for ESR/Thunderbird) to receive the compiler fix.

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:< 112.0
Firefox EsrWeb browser
Affected:< 102.10
Firefox MobileWeb browser
Affected:< 112.0
FocusApplication
Affected:< 112.0
ThunderbirdApplication
Affected:< 102.10

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
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/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. Check installed Mozilla product version
    Open the application and navigate to Help > About (Firefox/Thunderbird) or check your app settings (Focus). Alternatively, visit about:support in Firefox/Thunderbird to view the version number.
    Affected if The version is below 112.0 for Firefox/Focus, or below 102.10 for Firefox ESR/Thunderbird
  2. Confirm 64-bit ARM architecture
    Check system information - on Linux run 'uname -m' or 'dpkg --print-architecture'; on Android check Settings > About Phone > Processor architecture. The system must be aarch64 or armv8 64-bit.
    Affected if Running on 64-bit ARM (aarch64/armv8) architecture - the Ion JIT bug only affects ARM64 builds
  3. Verify Ion JIT compiler is enabled
    In Firefox or Thunderbird, type 'about:config' in the address bar, search for 'ion' and check if 'javascript.options.ion' is set to true (enabled by default on ARM64).
    Affected if Ion JIT compiler is enabled (javascript.options.ion = true) - the bug only manifests when Ion compilation is active

You are affected if you run Firefox < 112.0, Firefox ESR < 102.10, Thunderbird < 102.10, or Focus < 112.0 on a 64-bit ARM device with Ion JIT enabled.

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 102.10 / 112.0 or later
Fixed in 102.10112.0
Interim mitigation

Update affected Mozilla products (Firefox, Firefox ESR, Thunderbird, Focus for Android) to versions 112 or later (or 102.10 for ESR/Thunderbird) to receive the compiler fix.

Recommended fix High confidence

Firefox 112.0 (or Firefox ESR 102.10, Focus 112.0, Thunderbird 102.10)

  1. Check current Firefox version via Help > About Firefox
  2. Download Firefox 112.0 or later from official Mozilla website (www.mozilla.org)
  3. Install the updated Firefox version
  4. For Android devices, update Firefox for Android or Focus to version 112.0 or later
  5. For enterprise environments using Firefox ESR, upgrade to version 102.10 or later
  6. For Thunderbird users, upgrade to version 102.10 or later
  7. Restart the browser after update to ensure all components are loaded
Caveat Minor release updates; review Mozilla release notes for any add-on compatibility or feature changes

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

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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-2023-29548 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