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NVD / CVE Program· CNA Linux

CVE-2026-46076: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 009c0f726abeaa67aad1d96b883bdce01d405ce2, 5fb4a5f361565f5b629d8a8fe5288ce8463c5727, 924d721fae95687acedbaf624a094ed0e8b67104; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 009c0f726abeaa67aad1d96b883bdce01d405ce2, 5fb4a5f361565f5b629d8a8fe5288ce8463c5727, 924d721fae95687acedbaf624a094ed0e8b67104; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]

HighCVSS 7.9 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 21, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.9
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.

Get told when this record changes

  • 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 EPSS rises 20 points in a week

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.2 and later · before 6.12.86
  • linux linux kernel6.13 and later · before 6.18.27
  • linux linux kernel6.19 and later · before 7.0.4

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

    • 6.2affected
    • 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 and later · before fcef67506c0234935cb0fb026740a637edb58d7caffected · git
    • 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 and later · before 924d721fae95687acedbaf624a094ed0e8b67104affected · git
    • 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 and later · before 009c0f726abeaa67aad1d96b883bdce01d405ce2affected · git
    • 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 and later · before 5fb4a5f361565f5b629d8a8fe5288ce8463c5727affected · git
    • 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 and later · before c36991c6f8d2ab56ee67aff04e3c357f45cfc76caffected · git
    • before 6.2not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver
    • 6.12.86 and later · up to and including 6.12.*not affected · semver
    • 6.18.27 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
AlmaLinux:10kernelbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.61.1.el10_26.12.0-211.61.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-46070May 27, 2026 · md/raid5: validate payload size before accessing journal metadata
    28Monitor
  • ← EarlierCVE-2026-46071May 27, 2026 · KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12
    22Monitor
  • Later →CVE-2026-46078May 27, 2026 · erofs: fix the out-of-bounds nameoff handling for trailing dirents
    28Monitor

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 Linux009c0f726abeaa67aad1d96b883bdce01d405ce2Vendor (CNA)
Linux Linux5fb4a5f361565f5b629d8a8fe5288ce8463c5727Vendor (CNA)
Linux Linux924d721fae95687acedbaf624a094ed0e8b67104Vendor (CNA)
Linux Linuxc36991c6f8d2ab56ee67aff04e3c357f45cfc76cVendor (CNA)
Linux Linuxfcef67506c0234935cb0fb026740a637edb58d7cVendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
almalinux:kernel6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel-matched6.12.0-211.61.1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:linux6.12.86-1 · Debian:13Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:kernel-debuginfo0:6.12.0-211.61.1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)

+12

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.

  • CVE-2026-6383053 days apartnet: skmsg: preserve sg.copy across SG transforms
    37Monitor
  • CVE-2026-4333419 days apartBluetooth: SMP: force responder MITM requirements before building the pairing response
    35Monitor
  • CVE-2026-5307528 days apartppp: require CAP_NET_ADMIN in target netns for unattached ioctls
    35Monitor
  • CVE-2026-5290923 days apartip6_vti: set netns_immutable on the fallback device.
    31Monitor
  • CVE-2026-461501 days apartfanotify: fix false positive on permission events
    28Monitor

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.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · 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
Low
User interaction
None
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
High

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (4 more)

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

All records