A flaw was found in the Linux kernel's memory deduplication mechanism. The max page sharing of Kernel Samepage Merging (KSM), added in Linux kernel version 4.4.0-96.119, can create a side channel. When the attacker and the victim share the same host and the default setting of KSM is "max page sharing=256", it is possible for the attacker to time the unmap to merge with the victim's page. The unmapping time depends on whether it merges with the victim's page and additional physical pages are created beyond the KSM's "max page share". Through these operations, the attacker can leak the victim's page.
CVSS Details
- CVSS 3.1 Base Score: 5.3
- CVSS 3.1 Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | No solution exists | May 15, 2025 | Jan 30, 2024 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Jan 30, 2024 |
| Ubuntu | — | No solution exists | Jun 26, 2025 | Jan 30, 2024 |
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