Is there a patch available for CVE-2026-99258?

Yes, a patch is available for CVE-2026-99258. Update the affected software to the latest version immediately.

Linux CVE-2026-99258

EUVD-2026-115769

2026-11-03 Linux

GHSA-4pvm-qh3q-ccrf

Information Disclosure Linux

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Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Patch available

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AnalysisCVE.org

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.

Affected VersionsENISA

Linux patch: 6.12.115

Linux patch: 6.18.59

Linux 86c48271e0d60c82665e9fd61277002391efcef7 <7b74c117e2aac78e0f723e1c9c3644451c56b0d9

Linux patch: 7.2.13

Linux patch: 7.3

Linux 6.15.3 <6.16

Linux 3d12349ade541eefde0e71bf5c4aa7aa04c52a79 <bdba5f1b8bd0d18b1df61f769b559ed272902489

Linux 6.12.41 <6.12.115

Linux 86c48271e0d60c82665e9fd61277002391efcef7 <bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9

Linux cb002d6c8f06d6061e84b2109cb84416107a9fb9

Linux patch: 0

Linux 6.16

Linux 86c48271e0d60c82665e9fd61277002391efcef7 <2b561786c9076a892ef8b8f416c9828bc87ed44f

Affected Packages

euvd linux fix: 6.12.115, 6.16

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Exploit and PoC references, threat intelligence from 22 sources

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Lifecycle Timeline

Patch available

Nov 03, 2026 - 12:16 EUVD

CVE Published

Nov 03, 2026 - 11:25 cve.org

UNKNOWN (no severity yet)

Threat Intelligence Overview

Data Quality

1 sources

Confidence: Low

EUVD

CVE.org

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity Not scored yet

CISA KEV No

Public POC No

EPSS N/A

Patch available Yes

Active threat No

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.