FirefoxWeb browser · Mozilla
CVE-2022-22745
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 · uneditedSecuritypolicyviolation events could have leaked cross-origin information for frame-ancestors violations. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.
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 confidenceThe SecurityPolicyViolation event handler in affected Firefox and Thunderbird versions leaked cross-origin information when a frame-ancestors Content Security Policy violation occurred. This allowed a malicious page to potentially determine whether a target page exists on a different origin by observing violation events, enabling cross-origin reconnaissance.
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
< 96.0
Firefox EsrWeb browser
< 91.5< 91.5CVSS 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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Identify installed Firefox versionOpen Firefox, go to Help > About Firefox (or navigate to about:support). Locate the 'Version' field in the application details.Affected if The version number is below 96.0 (for example 95.x or earlier)
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Identify installed Firefox ESR versionOpen Firefox ESR, go to Help > About Firefox ESR. Locate the 'Version' field.Affected if The version number is below 91.5 (for example 91.4.x or earlier)
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Identify installed Thunderbird versionOpen Thunderbird, go to Help > About Thunderbird. Locate the 'Version' field.Affected if The version number is below 91.5 (for example 91.4.x or earlier)
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Verify CSP frame-ancestors policy in useIf you manage web applications, review their Content-Security-Policy headers for the 'frame-ancestors' directive using browser devtools (Network tab) or by inspecting HTTP response headers.Affected if frame-ancestors CSP is deployed and the browser version is affected - the event handler could leak information about cross-origin page existence
A user is affected if their installed Firefox (including ESR) is below version 96.0 (or below 91.5 for ESR) or Thunderbird is below version 91.5, and they browse web content that could exploit the SecurityPolicyViolation event leak.
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 · scoped91.596.0
Update affected installations to Firefox ESR 91.5+, Firefox 96+, or Thunderbird 91.5+ to patch the information leak in the SecurityPolicyViolation event handling.
Firefox 96.0, Firefox ESR 91.5, or Thunderbird 91.5 (depending on product)
- Upgrade Firefox to version 96.0 or later
- If using Firefox ESR, upgrade to version 91.5 or later
- If using Thunderbird, upgrade to version 91.5 or later
- After upgrading, verify the version by navigating to 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
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-22745 — 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-2022-22745 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