Browser-window spoofing via stale fullscreen state
Published Dec 22, 2022 · Updated Apr 16, 2025
Fullscreen handling in Firefox before 96, Firefox ESR before 91.5, and Thunderbird before 91.5 allows remote attackers to spoof browser chrome. Navigation from a fullscreen cross-origin iframe can retain a BFCache window actor, preventing normal fullscreen-state cleanup after the parent page changes. A user must interact with an attacker-controlled page and permit fullscreen; the resulting tab can remain fullscreen and imitate trusted browser interface elements.
Summary
What happened
Fullscreen handling in Firefox before 96, Firefox ESR before 91.5, and Thunderbird before 91.5 allows remote attackers to spoof browser chrome. Navigation from a fullscreen cross-origin iframe can retain a BFCache window actor, preventing normal fullscreen-state cleanup after the parent page changes. A user must interact with an attacker-controlled page and permit fullscreen; the resulting tab can remain fullscreen and imitate trusted browser interface elements.
The record
- CVE
- CVE-2022-22743
- Published
- Dec 22, 2022
- Updated
- Apr 16, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- T1656
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 2022CVE publishedPublication date reported by the CVE source.
- Apr 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <96
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Mozilla Bugzilla fullscreen reproduction caseproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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