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CVE-2026-62430

x86: Out-of-bounds read in vRTC emulation

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
None
Availability
None

Exploit likelihood

0.24%Unchanged since Jul 29, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

x86: Out-of-bounds read in vRTC emulation

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.

Record
CVE-2026-62430
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-362
Updated
2026-11-02
EUVDEUVD-2026-49783 7.5

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.

Record
EUVD-2026-49783
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-w4qm-qcx6-wmw8 7.5

Accesses to the CMOS memory contents are done using an indirect IO port pair. Therefore Xen...

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.

Record
GHSA-w4qm-qcx6-wmw8
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-362
Updated
2026-11-02
NVD 7.5

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.

Record
CVE-2026-62430
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-362
Updated
2026-11-02
OSVALPINE-CVE-2026-62430 7.5

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.

Record
ALPINE-CVE-2026-62430
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVDEBIAN-CVE-2026-62430 7.5

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.

Record
DEBIAN-CVE-2026-62430
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
Show 7 moreShow less
OSVUBUNTU-CVE-2026-62430 7.5

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.

Record
UBUNTU-CVE-2026-62430
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVopenSUSE-SU-2026:11441-1 No score

xen-4.22.0_02-1.1 on GA media

These are all security issues fixed in the xen-4.22.0_02-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11441-1
Updated
2026-11-02
OSVSUSE-SU-2026:3409-1 No score

Security update for xen

This update for xen fixes the following issues

  • CVE-2026-42493: x86 shadow paging is deprecated (bsc#1271528).
  • CVE-2026-42494,CVE-2026-42495,CVE-2026-62423,CVE-2026-62424,CVE-2026-62425: buffer overruns in libfsimage iso9660 handling (bsc#1271530).
  • CVE-2026-62426,CVE-2026-62427: sysctl and platform-op locks open to abuse (bsc#1271531).
  • CVE-2026-62428: grant-table: type confusion in grant-copy (bsc#1271532).
  • CVE-2026-62429: vNUMA domain cleanup may race other operations (bsc#1271534).
  • CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation (bsc#1271535).
  • CVE-2026-62431: Viridian STIMER division by zero (bsc#1271536).
  • CVE-2026-62432: evtchn: Race between FIFO expand and reset (bsc#1271537).
  • CVE-2026-62433: correct buffer checks for DM_OP hypercalls (bsc#1271538).
  • CVE-2026-62434: PoD: Don't try to reclaim special pages (bsc#1271539).
  • pygrub is only supported in de-privileged mode (XSA-508) (bsc#1271947).
Record
SUSE-SU-2026:3409-1
Updated
2026-11-02
OSVSUSE-SU-2026:3423-1 No score

Security update for xen

This update for xen fixes the following issues

  • CVE-2026-42493: x86 shadow paging is deprecated (bsc#1271528).
  • CVE-2026-42494,CVE-2026-42495,CVE-2026-62423,CVE-2026-62424,CVE-2026-62425: buffer overruns in libfsimage iso9660 handling (bsc#1271530).
  • CVE-2026-62426,CVE-2026-62427: sysctl and platform-op locks open to abuse (bsc#1271531).
  • CVE-2026-62428: grant-table: type confusion in grant-copy (bsc#1271532).
  • CVE-2026-62429: vNUMA domain cleanup may race other operations (bsc#1271534).
  • CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation (bsc#1271535).
  • CVE-2026-62431: Viridian STIMER division by zero (bsc#1271536).
  • CVE-2026-62432: evtchn: Race between FIFO expand and reset (bsc#1271537).
  • CVE-2026-62433: correct buffer checks for DM_OP hypercalls (bsc#1271538).
  • CVE-2026-62434: PoD: Don't try to reclaim special pages (bsc#1271539).
  • pygrub is only supported in de-privileged mode (XSA-508) (bsc#1271947).
Record
SUSE-SU-2026:3423-1
Updated
2026-11-02
OSVSUSE-SU-2026:3451-1 No score

Security update for xen

This update for xen fixes the following issues

  • CVE-2026-42493: x86 shadow paging is deprecated (bsc#1271528).
  • CVE-2026-42494,CVE-2026-42495,CVE-2026-62423,CVE-2026-62424,CVE-2026-62425: buffer overruns in libfsimage iso9660 handling (bsc#1271530).
  • CVE-2026-62426,CVE-2026-62427: sysctl and platform-op locks open to abuse (bsc#1271531).
  • CVE-2026-62428: grant-table: type confusion in grant-copy (bsc#1271532).
  • CVE-2026-62429: vNUMA domain cleanup may race other operations (bsc#1271534).
  • CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation (bsc#1271535).
  • CVE-2026-62432: evtchn: Race between FIFO expand and reset (bsc#1271537).
  • CVE-2026-62433: correct buffer checks for DM_OP hypercalls (bsc#1271538).
  • CVE-2026-62434: PoD: Don't try to reclaim special pages (bsc#1271539).
  • pygrub is only supported in de-privileged mode (XSA-508) (bsc#1271947).
Record
SUSE-SU-2026:3451-1
Updated
2026-11-02
OSVSUSE-SU-2026:3462-1 No score

Security update for xen

This update for xen fixes the following issues

  • CVE-2026-42493: x86 shadow paging is deprecated (bsc#1271528).
  • CVE-2026-42494,CVE-2026-42495,CVE-2026-62423,CVE-2026-62424,CVE-2026-62425: buffer overruns in libfsimage iso9660 handling (bsc#1271530).
  • CVE-2026-62426,CVE-2026-62427: sysctl and platform-op locks open to abuse (bsc#1271531).
  • CVE-2026-62428: grant-table: type confusion in grant-copy (bsc#1271532).
  • CVE-2026-62429: vNUMA domain cleanup may race other operations (bsc#1271534).
  • CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation (bsc#1271535).
  • CVE-2026-62431: Viridian STIMER division by zero (bsc#1271536).
  • CVE-2026-62432: evtchn: Race between FIFO expand and reset (bsc#1271537).
  • CVE-2026-62433: correct buffer checks for DM_OP hypercalls (bsc#1271538).
  • CVE-2026-62434: PoD: Don't try to reclaim special pages (bsc#1271539).
  • pygrub is only supported in de-privileged mode (XSA-508) (bsc#1271947).
Record
SUSE-SU-2026:3462-1
Updated
2026-11-02
OSVSUSE-SU-2026:4090-1 No score

Security update for xen

This update for xen fixes the following issues:

Update to version 4.20.3 (jsc#PED-8907).

Security issues fixed:

  • CVE-2026-42493: x86 shadow paging is deprecated (bsc#1271528).
  • CVE-2026-42494,CVE-2026-42495,CVE-2026-62423,CVE-2026-62424,CVE-2026-62425: buffer overruns in libfsimage iso9660 handling (bsc#1271530).
  • CVE-2026-62426,CVE-2026-62427: sysctl and platform-op locks open to abuse (bsc#1271531).
  • CVE-2026-62428: grant-table: type confusion in grant-copy (bsc#1271532).
  • CVE-2026-62429: vNUMA domain cleanup may race other operations (bsc#1271534).
  • CVE-2026-62430: x86: Out-of-bounds read in vRTC emulation (bsc#1271535).
  • CVE-2026-62431: Viridian STIMER division by zero (bsc#1271536).
  • CVE-2026-62432: evtchn: Race between FIFO expand and reset (bsc#1271537).
  • CVE-2026-62433: correct buffer checks for DM_OP hypercalls (bsc#1271538).
  • CVE-2026-62434: PoD: Don't try to reclaim special pages (bsc#1271539).
  • CVE-2026-62437: x86: DMs may cause mem leak by IRQ binding (bsc#1276838).
  • CVE-2026-79602: x86: improper handling of HVM emulation return codes (bsc#1276839).
  • CVE-2026-79603: unconditionally do TLB flushing ahead of page scrubbing (bsc#1276841).
  • pygrub is only supported in de-privileged mode (bsc#1271947).

Non security issue fixed:

  • Xen: Missing upstream bug fixes (bsc#1027519).
Record
SUSE-SU-2026:4090-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
xen
Alpine:v3.21
 before 4.19.6-r0
4.19.6-r0
xen
Alpine:v3.22
 before 4.20.4-r0
4.20.4-r0
xen
Alpine:v3.23
 before 4.20.4-r0
4.20.4-r0
xen
Alpine:v3.24
 before 4.21.2-r0
4.21.2-r0
xen
Debian:12
 before 4.17.7-0+deb12u1, plus listed versions
4.17.1+2-gb773c48e36-14.17.2+55-g0b56bed864-14.17.2+76-ge1f9cb16e2-14.17.2+76-ge1f9cb16e2-1~deb12u14.17.2-1
Show 9 moreShow less
4.17.3+10-g091466ba55-14.17.3+10-g091466ba55-1.14.17.3+10-g091466ba55-1.1~exp14.17.3+10-g091466ba55-1.1~exp24.17.3+10-g091466ba55-1~deb12u14.17.3+36-g54dacb5c02-14.17.5+23-ga4e5191dc0-14.17.5+23-ga4e5191dc0-1+deb12u14.17.5+72-g01140da4e8-1
4.17.7-0+deb12u1
xen
Debian:13
 before 4.20.3+127-gc42374a105-0+deb13u1, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+37-g61ff35323e-0+deb13u14.20.2+37-g61ff35323e-14.20.2+7-g1badcf5035-0+deb13u14.20.2+7-g1badcf5035-14.20.2+7-g1badcf5035-2
4.20.3+127-gc42374a105-0+deb13u1
xen
Debian:14
 before 4.20.3+127-gc42374a105-1, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+37-g61ff35323e-14.20.2+7-g1badcf5035-14.20.2+7-g1badcf5035-2
4.20.3+127-gc42374a105-1
xen
SUSE:Linux Enterprise Server 15 SP6-LTSS
 before 4.18.5_20-150600.3.53.3
4.18.5_20-150600.3.53.3
xen
SUSE:Linux Enterprise Server for SAP Applications 15 SP6
 before 4.18.5_20-150600.3.53.3
4.18.5_20-150600.3.53.3
xen
SUSE:Linux Enterprise Micro 5.5
 before 4.17.6_14-150500.3.76.3
4.17.6_14-150500.3.76.3
Show 22 moreShow less
Affected packages
PackageAffectedFixed
xen
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS
 before 4.17.6_14-150500.3.76.3
4.17.6_14-150500.3.76.3
xen
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS
 before 4.17.6_14-150500.3.76.3
4.17.6_14-150500.3.76.3
xen
SUSE:Linux Enterprise Server 15 SP5-LTSS
 before 4.17.6_14-150500.3.76.3
4.17.6_14-150500.3.76.3
xen
SUSE:Linux Enterprise Server for SAP Applications 15 SP5
 before 4.17.6_14-150500.3.76.3
4.17.6_14-150500.3.76.3
xen
SUSE:Linux Enterprise Server 12 SP5-LTSS
 before 4.12.4_72-3.148.4
4.12.4_72-3.148.4
xen
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5
 before 4.12.4_72-3.148.4
4.12.4_72-3.148.4
xen
SUSE:Linux Enterprise Micro 5.3
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise Micro 5.4
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise Server 15 SP4-LTSS
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise Server for SAP Applications 15 SP4
 before 4.16.7_12-150400.4.89.3
4.16.7_12-150400.4.89.3
xen
SUSE:Linux Enterprise Module for Basesystem 15 SP7
 before 4.20.4_04-150700.3.46.1
4.20.4_04-150700.3.46.1
xen
SUSE:Linux Enterprise Module for Server Applications 15 SP7
 before 4.20.4_04-150700.3.46.1
4.20.4_04-150700.3.46.1
xen
Ubuntu:16.04:LTS
 All versions, plus listed versions
4.5.1-0ubuntu14.5.1-0ubuntu24.6.0-1ubuntu14.6.0-1ubuntu24.6.0-1ubuntu4
Show 7 moreShow less
4.6.0-1ubuntu4.14.6.0-1ubuntu4.24.6.0-1ubuntu4.34.6.5-0ubuntu14.6.5-0ubuntu1.14.6.5-0ubuntu1.24.6.5-0ubuntu1.4
 None known
xen
Ubuntu:18.04:LTS
 All versions, plus listed versions
4.9.0-0ubuntu34.9.0-0ubuntu44.9.2-0ubuntu1
 None known
xen
Ubuntu:20.04:LTS
 All versions, plus listed versions
4.9.2-0ubuntu24.9.2-0ubuntu64.9.2-0ubuntu74.11.3+24-g14b62ab3e5-1ubuntu14.11.3+24-g14b62ab3e5-1ubuntu24.11.3+24-g14b62ab3e5-1ubuntu2.24.11.3+24-g14b62ab3e5-1ubuntu2.3
 None known
xen
Ubuntu:22.04:LTS
 All versions, plus listed versions
4.11.4+24-gddaaccbbab-1ubuntu24.16.0-1~ubuntu24.16.0-1~ubuntu2.1
 None known
xen
Ubuntu:24.04:LTS
 All versions, plus listed versions
4.17.2-14.17.2+55-g0b56bed864-14.17.2+76-ge1f9cb16e2-14.17.2+76-ge1f9cb16e2-1ubuntu14.17.3+10-g091466ba55-14.17.3+10-g091466ba55-1.1ubuntu24.17.3+10-g091466ba55-1.1ubuntu3
 None known
xen
Ubuntu:26.10
 All versions, plus listed versions
4.20.2+7-g1badcf5035-2build24.20.2+37-g61ff35323e-1ubuntu14.20.3+127-gc42374a105-1
 None known
xen
Ubuntu:26.04:LTS
 All versions, plus listed versions
4.20.0+68-g35cb38b222-14.20.2+7-g1badcf5035-24.20.2+7-g1badcf5035-2build2
 None known
xen
openSUSE:Tumbleweed
 before 4.22.0_02-1.1
4.22.0_02-1.1

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-62430 is a high vulnerability (CVSS 7.5) in Xen, published July 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. Fixed in xen 4.19.6-r0.

References

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