Allocation-tag exposure via uncleared huge zero folio
Published Jul 19, 2026 · Updated Jul 19, 2026
Use of uninitialized MTE tags in Linux Kernel 6.18 exposes stale allocation tags to local users through a huge zero folio. In post_alloc_hook(), __GFP_ZEROTAGS suppresses tag clearing after init_on_free has already cleared page content, while the special PMD mapping bypasses later tag initialization. The condition requires an affected arm64 MTE kernel, init_on_free enabled, and a huge zero folio; the public record establishes no memory-corruption path.
Summary
What happened
Use of uninitialized MTE tags in Linux Kernel 6.18 exposes stale allocation tags to local users through a huge zero folio. In post_alloc_hook(), __GFP_ZEROTAGS suppresses tag clearing after init_on_free has already cleared page content, while the special PMD mapping bypasses later tag initialization. The condition requires an affected arm64 MTE kernel, init_on_free enabled, and a huge zero folio; the public record establishes no memory-corruption path.
The record
- CVE
- CVE-2026-64130
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-908
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 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=6.18
- Affected versionversion=adfb6609c6809e107ded9a1cd46f519c882e64ea <2f2aec5120b93a8f8b52dc50cdc60dbb8aec72f6
- Affected versionversion=adfb6609c6809e107ded9a1cd46f519c882e64ea <6a288a4ddb4a994490505ab5f41c445f8e6b6467
- Affected versionversion=adfb6609c6809e107ded9a1cd46f519c882e64ea <738d18f1da3513d17b6f7bf30146cc4ac2480ffd
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
Your stack
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Your stack
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