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CVE-2026-89930· NVD / CVE Program· CNA Linux

KVM: nVMX: Service local TLB flushes on failed nested VM-Enter

Noroxi assessment

Priority: Monitor (action score 37/100)

  • 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: 0.18% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 05a0b701d1089fb57beeb8982f23c3bbafe0fa8b, 1025b938dc439b75c720a568a855a13eeb245686, 312cdb6d8940827dea63a7a52fb714a5049f06d1; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 05a0b701d1089fb57beeb8982f23c3bbafe0fa8b, 1025b938dc439b75c720a568a855a13eeb245686, 312cdb6d8940827dea63a7a52fb714a5049f06d1; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 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: KVM: nVMX: Service local TLB flushes on failed nested VM-Enter KVM services local TLB flushes on "full" nested VM-Exits (through __nested_vmx_vmexit()), but not if a nested VM-Enter fails (e.g. due to failed VMCS checks in nested_vmx_enter_non_root_mode()). However, it is possible that KVM had queued TLB flushes that need to be performed, even if the nested VM-Enter was not successful. For example, if VPID is disabled for L2 (via nested_vmx_transition_tlb_flush(), or if via the MSR load lists, as the SDM says: If any MSR is being loaded in such a way that would architecturally require a TLB flush, the TLBs are updated so that, after VM entry, the logical processor will not use any translations that were cached before the transition. The SDM is unclear about when the TLB flush should occur, and whether or not a failed VM entry would flush the TLB, so it is safer to always do the TLB flush in this case. More concretely, KVM also updates the last VPID L1 used for L2 in nested_vmx_transition_tlb_flush() (i.e. last_vpid), even if the VM entry ultimately fails. With the current code, KVM could miss a TLB flush if L1 changes L2's VPID, then does a failed VM entry followed by a successful one, as the failed VM entry would update last_vpid but not actually flush the TLB. Servicing local TLB flushes on failed VM entries makes sure that the TLB is always flushed when last_vpid is updated.

CriticalCVSS 9.3 · v3.1—No exploit Fix available
Published
Sep 16, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

37

Monitor

Low priority for now.

CVSS
37 / 40 · 9.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
9.3
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

    • 4.4affected
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before c0c66cd575e31218da6a7d104c6ef80b0830b60caffected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before 1025b938dc439b75c720a568a855a13eeb245686affected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before 312cdb6d8940827dea63a7a52fb714a5049f06d1affected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before f74fccdf4f7fb0780cd84944108d35f3d9dc46a7affected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before c43563e7518e65ec6ccaa6a65f84c5af5ca5d379affected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before 62c3ee4c9f0e2efef5157358b3549e50ede96d73affected · git
    • 5c614b3583e7b6dab0c86356fa36c2bcbb8322a0 and later · before 05a0b701d1089fb57beeb8982f23c3bbafe0fa8baffected · git
    • before 4.4not affected · semver
    • 5.15.221 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

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-2026-89928Sep 16, 2026 · KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk
    35Monitor
  • ← EarlierCVE-2026-89929Sep 16, 2026 · KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU
    35Monitor
  • Later →CVE-2026-89931Sep 16, 2026 · KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
    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 Linux05a0b701d1089fb57beeb8982f23c3bbafe0fa8bVendor (CNA)
Linux Linux1025b938dc439b75c720a568a855a13eeb245686Vendor (CNA)
Linux Linux312cdb6d8940827dea63a7a52fb714a5049f06d1Vendor (CNA)
Linux Linux62c3ee4c9f0e2efef5157358b3549e50ede96d73Vendor (CNA)
Linux Linuxc0c66cd575e31218da6a7d104c6ef80b0830b60cVendor (CNA)
Linux Linuxc43563e7518e65ec6ccaa6a65f84c5af5ca5d379Vendor (CNA)
Linux Linuxf74fccdf4f7fb0780cd84944108d35f3d9dc46a7Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package 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.

No dated events beyond publication.

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

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

nvd-secondary

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. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records