FirefoxWeb browser · Mozilla
CVE-2022-45403
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 · uneditedService Workers should not be able to infer information about opaque cross-origin responses; but timing information for cross-origin media combined with Range requests might have allowed them to determine the presence or length of a media file. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.
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 confidenceService Workers could use timing information from cross-origin media requests combined with Range requests to determine the presence or length of media files, bypassing the protection that opaque responses should provide. This creates a timing side-channel that leaks information about cross-origin resources.
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
< 107.0
Firefox EsrWeb browser
< 102.5< 102.5CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Firefox versionNavigate to Firefox menu > Help > About Firefox, or enter 'about:support' in the address bar and look for the Version fieldAffected if The version displayed is earlier than 107.0 (for regular Firefox)
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Check installed Firefox ESR versionNavigate to Firefox menu > Help > About Firefox, or enter 'about:support' in the address bar and look for the Version fieldAffected if The version displayed is earlier than 102.5 (for Firefox ESR)
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Check installed Thunderbird versionNavigate to Thunderbird menu > Help > About Thunderbird, and look for the Version fieldAffected if The version displayed is earlier than 102.5 (for Thunderbird)
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Verify Service Worker statusEnter 'about:serviceworkers' in the Firefox address bar and check if any Service Workers are registeredAffected if Service Workers are enabled and active - this is the vulnerable feature that must be present for exploitation
You are affected if you are running Firefox < 107.0, Firefox ESR < 102.5, or Thunderbird < 102.5 AND you have Service Workers enabled in your browser.
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 · scoped102.5107.0
Update affected software to Firefox 107+, Firefox ESR 102.5+, or Thunderbird 102.5+ to patch the timing side-channel in Service Workers.
Firefox 107.0, Firefox ESR 102.5, Thunderbird 102.5
- Open Firefox or Thunderbird
- Navigate to the Help menu (or click the menu icon)
- Select 'About Firefox' or 'About Thunderbird'
- The application will check for updates and download version 107.0 (Firefox) or 102.5 (Thunderbird/ESR)
- Restart the application to complete the update
- Alternatively, download the latest version directly from https://www.mozilla.org/
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 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-2022-45403 — 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-2022-45403 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