Kernel-address disclosure via BPF_FETCH verifier type confusion
Published Jun 19, 2024 · Updated May 11, 2026
Information disclosure in the Linux kernel 5.12 through 5.15.10 allows local users to leak kernel pointers through eBPF. The eBPF verifier's check_mem_access() path treats a BPF_FETCH result from a spilled stack pointer as a scalar without first rejecting the pointer read, allowing the value to be written to a map. Unprivileged BPF access and the ability to load a crafted program are required; the disclosure exposes kernel addresses without modifying data or interrupting service.
Summary
What happened
Information disclosure in the Linux kernel 5.12 through 5.15.10 allows local users to leak kernel pointers through eBPF. The eBPF verifier's check_mem_access() path treats a BPF_FETCH result from a spilled stack pointer as a scalar without first rejecting the pointer read, allowing the value to be written to a map. Unprivileged BPF access and the ability to load a crafted program are required; the disclosure exposes kernel addresses without modifying data or interrupting service.
The record
- CVE
- CVE-2021-47608
- Published
- Jun 19, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 19, 2024CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record 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=37086bfdc737ea6f66bf68dcf16757004d68e1e1 <423628125a484538111c2c6d9bb1588eb086053b
- Affected versionversion=37086bfdc737ea6f66bf68dcf16757004d68e1e1 <7d3baf0afa3aa9102d6a521a8e4c41888bb79882
- Affected versionversion=5.12
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
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Public exploit references
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Technologies
Your stack
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Your stack
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