CVE-2026-62430

x86: Out-of-bounds read in vRTC emulation

HIGH
7.5
CVSS Score
Published: July 28, 2026 at 12:32 PM UTC
Updated: July 28, 2026 at 05:35 PM UTC
Products not identified yet

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Severity
HIGH7.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

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.

Affected

We have no canonical product record for this CVE. The source names may not have matched any product.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

Source: af854a3a-2127-422b-91ae-364da2661108
http://xenbits.xen.org/xsa/advisory-503.html
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/07/28/19

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-362

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