FirefoxWeb browser · Mozilla
CVE-2023-37456
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 · uneditedThe session restore helper crashed whenever there was no parameter sent to the message handler. This vulnerability affects Firefox for iOS < 115.
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 confidenceFirefox for iOS contains a vulnerability in the session restore helper where the message handler crashes when invoked without any parameters. This causes a denial of service through application crash, requiring the app to be force-closed and reopened. The vulnerability exists in versions prior to 115.
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
< 115CVSS 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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Confirm Firefox for iOS is installedCheck your device for the Firefox browser app - verify it is the iOS version (iPhone/iPad) and not Firefox for desktop or other platforms. Look for 'Firefox: Private Browser' or 'Firefox' in the App Store or on your device.Affected if The app is Firefox for iOS specifically.
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Check installed Firefox for iOS versionOpen the App Store, go to your profile, tap 'Purchased', find Firefox, or check within the app: tap the hamburger menu > Settings > About Firefox. Compare the version number against the affected range (versions prior to 115).Affected if The installed version is below 115 (e.g., 114.x, 113.x, etc.).
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Verify session restore is enabledWithin Firefox for iOS, tap the hamburger menu > Settings > Privacy. Check if 'Restore Tabs' or 'Close Tabs' settings are configured to restore previous sessions on app launch. The vulnerability triggers when the session restore message handler is invoked.Affected if Session restore is enabled and the app would attempt to restore tabs on launch.
You are affected if you have Firefox for iOS installed with a version number lower than 115 and session restore functionality is enabled, as the crash occurs when the session restore handler processes without required parameters.
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 · scoped115
Upgrade Firefox for iOS to version 115 or later to receive the patch that adds proper parameter validation to the session restore message handler.
Firefox for iOS 115
- 1. Open the App Store on your iOS device
- 2. Search for "Firefox" or "Firefox for iOS"
- 3. If an update is available, tap "Update" to install Firefox for iOS version 115 or later
- 4. Alternatively, enable automatic updates by going to Settings > App Store > Automatic Downloads and enabling Updates
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-37456 — 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-2023-37456 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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- 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
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