File-bounds check bypass via signed wraparound
Published Jul 25, 2026 · Updated Jul 25, 2026
Integer overflow in Linux Kernel 6.8 through 7.1.3 allows local users to bind a guest_memfd memslot beyond the file boundary. KVM adds an attacker-controlled unsigned offset and memslot size as signed loff_t values, so wraparound creates a negative sum that passes comparison with the positive inode size. Exploitation requires local access to KVM VM ioctls and an extreme offset; the public record establishes the invalid binding but no further consequence.
Summary
What happened
Integer overflow in Linux Kernel 6.8 through 7.1.3 allows local users to bind a guest_memfd memslot beyond the file boundary. KVM adds an attacker-controlled unsigned offset and memslot size as signed loff_t values, so wraparound creates a negative sum that passes comparison with the positive inode size. Exploitation requires local access to KVM VM ioctls and an extreme offset; the public record establishes the invalid binding but no further consequence.
The record
- CVE
- CVE-2026-64283
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-190
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2026CVE publishedPublication date reported by the CVE source.
- Jul 25, 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?
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- Affected versionversion=6.8
- Affected versionversion=a7800aa80ea4d5356b8474c2302812e9d4926fa6 <eba85fee7fc6cf28fec38a5bf3c378bef9a79ca6
- Affected versionversion=a7800aa80ea4d5356b8474c2302812e9d4926fa6 <f3a98d5881b9bd4807f49156143565f6aabcef1e
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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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