Memory disclosure via uninitialized encrypted stream padding
Published Dec 19, 2023 · Updated Feb 13, 2025
Uninitialized-memory disclosure in Mozilla Firefox before 121 and Firefox ESR before 115.6 allows attackers to write memory data to disk. EncryptingOutputStream encrypts only the actual payload but writes whole 4 KiB blocks, leaving unused bytes sourced from uninitialized process memory. The affected storage path serves IndexedDB and Cache API data in private browsing; reading the extra bytes requires a compromised content process or access to the profile directory.
Summary
What happened
Uninitialized-memory disclosure in Mozilla Firefox before 121 and Firefox ESR before 115.6 allows attackers to write memory data to disk. EncryptingOutputStream encrypts only the actual payload but writes whole 4 KiB blocks, leaving unused bytes sourced from uninitialized process memory. The affected storage path serves IndexedDB and Cache API data in private browsing; reading the extra bytes requires a compromised content process or access to the profile directory.
The record
- CVE
- CVE-2023-6865
- Published
- Dec 19, 2023
- Updated
- Feb 13, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- T1005
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 19, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 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 <121
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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