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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99258: x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
  • Fixed version: Linux Linux 2b561786c9076a892ef8b8f416c9828bc87ed44f, 6.12.115, 6.16.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2b561786c9076a892ef8b8f416c9828bc87ed44f, 6.12.115, 6.16 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Nov 3, 2026
Updated
Nov 3, 2026
EPSS
0.1% · 8th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • cb002d6c8f06d6061e84b2109cb84416107a9fb9, 6.16affected
    • 3d12349ade541eefde0e71bf5c4aa7aa04c52a79 and later · before bdba5f1b8bd0d18b1df61f769b559ed272902489affected · git
    • 86c48271e0d60c82665e9fd61277002391efcef7 and later · before 2b561786c9076a892ef8b8f416c9828bc87ed44faffected · git
    • 86c48271e0d60c82665e9fd61277002391efcef7 and later · before bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9affected · git
    • 86c48271e0d60c82665e9fd61277002391efcef7 and later · before 7b74c117e2aac78e0f723e1c9c3644451c56b0d9affected · git
    • 6.12.41 and later · before 6.12.115affected · semver
    • 6.15.3 and later · before 6.16affected · semver
    • before 6.16not affected · semver
    • 6.12.115 and later · up to and including 6.12.*not affected · semver
    • 6.18.59 and later · up to and including 6.18.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.115-16.12.115-1
Debian:14linuxfrom 0—

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-99256Nov 3, 2026 · dm cache: fix issue with background work locking
    0Monitor
  • ← EarlierCVE-2026-99257Nov 3, 2026 · gpio: shared: gracefully handle no-device lookup of shared GPIOs
    0Monitor
  • Later →CVE-2026-99259Nov 3, 2026 · soc/tegra: pmc: Fix uninitialised clock rate
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2b561786c9076a892ef8b8f416c9828bc87ed44fVendor (CNA)
Linux Linux6.12.115Vendor (CNA)
Linux Linux6.16Vendor (CNA)
Linux Linux7b74c117e2aac78e0f723e1c9c3644451c56b0d9Vendor (CNA)
Linux Linuxbc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9Vendor (CNA)
Linux Linuxbdba5f1b8bd0d18b1df61f769b559ed272902489Vendor (CNA)
debian:linux6.12.115-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 5, 2026+2 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records