UI spoofing via misrouted fullscreen exit messages
Published Aug 17, 2021 · Updated Aug 3, 2024
UI spoofing in Mozilla Firefox for Android before 91 allows remote attackers to trap users in fullscreen through a crafted webpage. GeckoView's fullscreen-exit path sends the exit message to the root browsing-context actor and its nonexistent ancestors instead of descendant frames, so a recursive iframe never receives the request. A user must open and interact with the page; the locked view can present convincing attacker-controlled interface content, but no data access or code execution is reported.
Summary
What happened
UI spoofing in Mozilla Firefox for Android before 91 allows remote attackers to trap users in fullscreen through a crafted webpage. GeckoView's fullscreen-exit path sends the exit message to the root browsing-context actor and its nonexistent ancestors instead of descendant frames, so a recursive iframe never receives the request. A user must open and interact with the page; the locked view can present convincing attacker-controlled interface content, but no data access or code execution is reported.
The record
- CVE
- CVE-2021-29983
- Published
- Aug 17, 2021
- Updated
- Aug 3, 2024
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 17, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record 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 <91
What conditions does exploitation require?
What is affected?
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
No sourced classifications are available.
Public exploit references
- fullscreen-persistent.fenix.htmlproof 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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