CVE-2026-89908LoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY
- 8.8HighCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: LoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY kvm_arch_prepare_memory_region() computes new->arch.flags, i.e. whether a memslot is KVM_MEM_HUGEPAGE_CAPABLE or KVM_MEM_HUGEPAGE_INCAPABLE, only for KVM_MR_CREATE and KVM_MR_MOVE, and returns early for every other change. But the generic code allocates a zeroed memslot for every change and never copies old->arch, so after a KVM_MR_FLAGS_ONLY update, e.g. toggling KVM_MEM_LOG_DIRTY_PAGES for live migration, the active memslot has arch.flags == 0. With both flags clear, fault_supports_huge_mapping() falls through to the alignment check on the HVA range alone, which no longer verifies that the GPA and HVA have the same offset within a PMD. A memslot that was marked KVM_MEM_HUGEPAGE_INCAPABLE because of a GPA/HVA offset mismatch can then be mapped with PMD entries on read faults, and since kvm_map_page() aligns the gfn and the pfn independently, the guest ends up accessing the wrong host pages, exactly the "d -> f, e -> g" case described in the comment above the check. Carry the arch flags over from the old memslot for KVM_MR_FLAGS_ONLY, as the GPA, HVA and size are guaranteed to be unchanged for that case.
Timeline
ID reserved
By Linux
- 5 days later
· 5 days later
Published
- 33 days later
· 33 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.18% · top 93% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Affected products
- affected 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c – < 7c6df65b53846cd7a9a1c81c6ddb42fdc08603e8
- affected 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c – < 4e4dbc341b1581dc512b85d98b768373b0398366
- affected 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c – < bc7a6849b4395f45a602db91b0fb2fb2e9ed4bba
- affected 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c – < 27a9bfee3bbcb3cabb77797354f07e0e44e49831
- affected 6.8
- unaffected < 6.8
- unaffected 6.12.110 – ≤ 6.12.*
- unaffected 6.18.51 – ≤ 6.18.*
- unaffected 7.2.5 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References4
- https://git.kernel.org/stable/c/7c6df65b53846cd7a9a1c81c6ddb42fdc08603e8 (opens in a new tab)
- https://git.kernel.org/stable/c/4e4dbc341b1581dc512b85d98b768373b0398366 (opens in a new tab)
- https://git.kernel.org/stable/c/bc7a6849b4395f45a602db91b0fb2fb2e9ed4bba (opens in a new tab)
- https://git.kernel.org/stable/c/27a9bfee3bbcb3cabb77797354f07e0e44e49831 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-80508 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-89908)Record last updated .