CVE-2026-99258
x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index() hv_apicid_to_vp_index() currently uses the per-cpu hypercall input and output pages. This function is called when running in VTL2 and when running in an SEV-SNP CoCo VM with no paravisor. In the former case, the output page is allocated, but in the latter case it is not, so the hypervisor stores the output VP index in memory that has not been allocated by the guest. Fix this by using the input page for both input and output. The hypercall has very small input and output, so sharing the same page for both is straightforward. An alternative fix is to allocate the per-cpu output page when running in an SEV-SNP CoCo guest, but this uses significantly more memory, particularly with larger vCPUs counts.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.19% · top 91% of all CVEs (6 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 3d12349ade541eefde0e71bf5c4aa7aa04c52a79 – < bdba5f1b8bd0d18b1df61f769b559ed272902489
- affected 86c48271e0d60c82665e9fd61277002391efcef7 – < 2b561786c9076a892ef8b8f416c9828bc87ed44f
- affected 86c48271e0d60c82665e9fd61277002391efcef7 – < bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9
- affected 86c48271e0d60c82665e9fd61277002391efcef7 – < 7b74c117e2aac78e0f723e1c9c3644451c56b0d9
- affected cb002d6c8f06d6061e84b2109cb84416107a9fb9
- affected 6.12.41 – < 6.12.115
- affected 6.15.3 – < 6.16
- affected 6.16
- unaffected < 6.16
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References (4)
- https://git.kernel.org/stable/c/bdba5f1b8bd0d18b1df61f769b559ed272902489 (opens in a new tab)
- https://git.kernel.org/stable/c/2b561786c9076a892ef8b8f416c9828bc87ed44f (opens in a new tab)
- https://git.kernel.org/stable/c/bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9 (opens in a new tab)
- https://git.kernel.org/stable/c/7b74c117e2aac78e0f723e1c9c3644451c56b0d9 (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)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2026-99258)Record last updated .