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NVD / CVE Program· CNA XEN

CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.24% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: xen (Alpine:v3.21) 4.19.6-r0; xen (Alpine:v3.22) 4.20.4-r0; xen (Alpine:v3.24) 4.21.2-r0.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to xen (Alpine:v3.21) 4.19.6-r0; xen (Alpine:v3.22) 4.20.4-r0; xen (Alpine:v3.24) 4.21.2-r0 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

Accesses to the CMOS memory contents are done using an indirect IO port pair. Therefore Xen needs to cache the guest chosen index, and one of the usages of the index didn't take the necessary locking to avoid concurrent changes. As a result, a guest could change the index after it being checked, causing a subsequent out-of-bound read access to the contents of an array.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Jul 28, 2026
Updated
Jul 28, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-62430

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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.

—

Versions reported by the vendor

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

  • Xen Xen

    • consult Xen advisory XSA-503unknown

Package-level exposure

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

EcosystemPackageAffected rangeFix
Alpine:v3.21xenbefore 4.19.6-r04.19.6-r0
Alpine:v3.22xenbefore 4.20.4-r04.20.4-r0
Alpine:v3.24xenbefore 4.21.2-r04.21.2-r0
Debian:12xenbefore 4.17.7-0+deb12u14.17.7-0+deb12u1
Debian:13xenbefore 4.20.3+127-gc42374a105-0+deb13u14.20.3+127-gc42374a105-0+deb13u1
Debian:14xenbefore 4.20.3+127-gc42374a105-14.20.3+127-gc42374a105-1
openSUSE:Tumbleweedxenbefore 4.22.0_02-1.14.22.0_02-1.1
SUSE:Linux Enterprise Micro 5.3xenbefore 4.16.7_12-150400.4.89.34.16.7_12-150400.4.89.3
SUSE:Linux Enterprise Micro 5.5xenbefore 4.17.6_14-150500.3.76.34.17.6_14-150500.3.76.3
SUSE:Linux Enterprise Module for Basesystem 15 SP7xenbefore 4.20.4_04-150700.3.46.14.20.4_04-150700.3.46.1
SUSE:Linux Enterprise Server 12 SP5-LTSSxenbefore 4.12.4_72-3.148.44.12.4_72-3.148.4
SUSE:Linux Enterprise Server 15 SP6-LTSSxenbefore 4.18.5_20-150600.3.53.34.18.5_20-150600.3.53.3

Same product

xen: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-10921The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, whi
    41Plan
  • CVE-2017-10920The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host
    41Plan
  • CVE-2017-10918Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-62428Jul 28, 2026 · grant-table: type confusion in grant-copy
    31Monitor
  • ← EarlierCVE-2026-62429Jul 28, 2026 · vNUMA domain cleanup may race other operations
    26Monitor
  • Later →CVE-2026-62431Jul 28, 2026 · Viridian STIMER division by zero
    30Monitor

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
alpine:xen4.19.6-r0 · Alpine:v3.21Package registry (OSV)
debian:xen4.17.7-0+deb12u1 · Debian:12Package registry (OSV)
debian:xen4.20.3+127-gc42374a105-0+deb13u1 · Debian:13Package registry (OSV)
opensuse:xen4.22.0_02-1.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:xen4.18.5_20-150600.3.53.3 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage 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.

  • CVE-2026-7961077 days apartgrant-table: double version change race
    35Monitor
  • CVE-2026-4248740 days apartx86 HVM I/O port list traversal
    31Monitor
  • CVE-2026-2355870 days apartgrant table v2 race in status page mapping
    31Monitor
  • CVE-2025-58145320 days apartArm issues with page refcounting
    30Monitor
  • CVE-2026-624320 days apartevtchn: Race between FIFO expand and reset
    29Monitor
  • CVE-2026-624290 days apartvNUMA domain cleanup may race other operations
    26Monitor

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

  • Anyone who can reach it over the internet 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
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

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

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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (2 more)

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

All records