Secret-key leakage via variable-time Base64 decoding
Published Jul 17, 2024 · Updated Aug 2, 2024
Observable timing discrepancy in Matrix.org vodozemac before 0.7.0 allows local users to infer secret key material via timing measurements. Megolm session-key and PkDecryption Ed25519 secret-key import paths decode Base64 input with a variable-time implementation instead of a constant-time decoder. Exploitation requires high-precision measurements and repeated access to the encoding or decoding operation; reported leakage is bounded.
Summary
What happened
Observable timing discrepancy in Matrix.org vodozemac before 0.7.0 allows local users to infer secret key material via timing measurements. Megolm session-key and PkDecryption Ed25519 secret-key import paths decode Base64 input with a variable-time implementation instead of a constant-time decoder. Exploitation requires high-precision measurements and repeated access to the encoding or decoding operation; reported leakage is bounded.
The record
- CVE
- CVE-2024-40640
- Published
- Jul 17, 2024
- Updated
- Aug 2, 2024
- Vendor
- Matrix.org
- Product
- vodozemac
- Classifications
- CWE-208
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 17, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 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=< 0.7.0
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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