Command execution via unescaped protocol-handler parameters
Published Dec 8, 2021 · Updated Aug 4, 2024
Command injection in Mozilla Firefox before 95, Firefox ESR before 91.4.0, and Thunderbird before 91.4.0 allows remote attackers to execute commands. The external-protocol launch path passed space-containing parameter URLs to registered handlers without percent-encoding the spaces, splitting one URL into multiple command-line arguments. Exploitation requires user activation of a crafted external-protocol URL and an installed handler that processes the injected argument unsafely; commands run with that handler's privileges.
Summary
What happened
Command injection in Mozilla Firefox before 95, Firefox ESR before 91.4.0, and Thunderbird before 91.4.0 allows remote attackers to execute commands. The external-protocol launch path passed space-containing parameter URLs to registered handlers without percent-encoding the spaces, splitting one URL into multiple command-line arguments. Exploitation requires user activation of a crafted external-protocol URL and an installed handler that processes the injected argument unsafely; commands run with that handler's privileges.
The record
- CVE
- CVE-2021-43541
- Published
- Dec 8, 2021
- Updated
- Aug 4, 2024
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 8, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 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 <95
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
Public exploit references
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Technologies
Your stack
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Your stack
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