CVE-2026-64561KVM: x86: Check for invalid/obsolete root *after* making MMU pages available
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Check for invalid/obsolete root *after* making MMU pages available Check for a "stale" page fault, i.e. for an invalid and/or obsolete root, after making MMU pages available for the shadow MMU. If reclaiming shadow pages zaps an in-use root, i.e. marks it invalid, then KVM will attempt to map memory into an invalid root. On its own, populating an invalid root is "fine", but because child shadow pages inherit their parent's role, any children created during the map/fetch will be created as invalid pages, thus violating KVM's invariant that invalid pages are never on the list of active MMU pages. Note, the underlying flaw has existed since KVM first started tracking invalid roots in 2008 (commit 2e53d63acba7, "KVM: MMU: ignore zapped root pagetables"), but the true badness only came along in 2020 (Linux 5.9) with the invariant that invalid shadow pages can't be on the list of active pages. Note #2, inheriting role.invalid when creating child shadow pages is also far from ideal; that flaw will be addressed separately.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from f95eec9bed76d42194c23153cb1cc8f186bf91cb before 62ef67af1878fa2cd066642f2f59e33ade95f637; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before 65c4f7a1028cf01a93a2762d679c289810ede990; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before 35e77467610c4a37cb0ff54ee56b85f73b1f5700; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before 0026dbb7de8ea76e97d6edf42fc3cc084564e2bf; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before f3477a6a4164f15287444eda685b5f6405dbd1e5; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before bce0d3c26e2c761a4bf43c8949f333fc7374eb2d; from f95eec9bed76d42194c23153cb1cc8f186bf91cb before 2abd5287f08319fa35764566b15c6e22cb1068db | CNA record |
References
- https://git.kernel.org/stable/c/62ef67af1878fa2cd066642f2f59e33ade95f637
- https://git.kernel.org/stable/c/65c4f7a1028cf01a93a2762d679c289810ede990
- https://git.kernel.org/stable/c/35e77467610c4a37cb0ff54ee56b85f73b1f5700
- https://git.kernel.org/stable/c/0026dbb7de8ea76e97d6edf42fc3cc084564e2bf
- https://git.kernel.org/stable/c/f3477a6a4164f15287444eda685b5f6405dbd1e5
- https://git.kernel.org/stable/c/bce0d3c26e2c761a4bf43c8949f333fc7374eb2d
- https://git.kernel.org/stable/c/2abd5287f08319fa35764566b15c6e22cb1068db
- https://github.com/V4bel/Zapscape
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.