DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.218-1vulnerable
bullseye (security)5.10.221-1vulnerable
bookworm (security)6.1.90-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


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