Signature verification tampering via temporary-file race condition
Published Jun 24, 2021 · Updated Aug 3, 2024
Race condition in OpenPGP signature verification in Mozilla Thunderbird before 78.10 allows local users to replace temporary signature data. The onStopRequest() path in mimeVerify.jsm writes PGP/MIME signature bytes to a predictable temporary file, then passes that filename to the RNP library, allowing the file to be swapped before RNP reads it. A malicious local process or user must win the timing race while a signed message is verified; Mozilla's assessment did not demonstrate a meaningful security consequence.
Summary
What happened
Race condition in OpenPGP signature verification in Mozilla Thunderbird before 78.10 allows local users to replace temporary signature data. The onStopRequest() path in mimeVerify.jsm writes PGP/MIME signature bytes to a predictable temporary file, then passes that filename to the RNP library, allowing the file to be swapped before RNP reads it. A malicious local process or user must win the timing race while a signed message is verified; Mozilla's assessment did not demonstrate a meaningful security consequence.
The record
- CVE
- CVE-2021-29948
- Published
- Jun 24, 2021
- Updated
- Aug 3, 2024
- Vendor
- Mozilla
- Product
- Thunderbird
- Classifications
- CWE-362
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Jun 24, 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?
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- Affected versionversion=unspecified <78.10
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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