Kernel-address disclosure via stale eBPF register bounds
Published Aug 24, 2022 · Updated Aug 3, 2024
Information disclosure in the Linux kernel before 5.7-rc1 allows local users to leak kernel addresses through crafted eBPF programs. The adjust_scalar_min_max_vals verifier path coerces arithmetic results without refreshing register bounds, leaving constant tnum data inconsistent with unsigned bounds. Exploitation requires permission to load eBPF code and exposes internal kernel locations that weaken address-based exploit mitigations, without reported data modification or service interruption.
Summary
What happened
Information disclosure in the Linux kernel before 5.7-rc1 allows local users to leak kernel addresses through crafted eBPF programs. The adjust_scalar_min_max_vals verifier path coerces arithmetic results without refreshing register bounds, leaving constant tnum data inconsistent with unsigned bounds. Exploitation requires permission to load eBPF code and exposes internal kernel locations that weaken address-based exploit mitigations, without reported data modification or service interruption.
The record
- CVE
- CVE-2021-4159
- Published
- Aug 24, 2022
- Updated
- Aug 3, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-497, CWE-202
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Aug 24, 2022CVE 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Fixed in v5.7-rc1
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
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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