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CVE-2026-63807

HIGH 8.8 ALL-YEARS

Published 2026-07-19 · Last modified 2026-10-19 · Linux · NVD: Modified

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level When recovering hugepages in the shadow MMU, verify that the base gfn of the shadow page is actually contained within the target memslot, *before* querying the max mapping level given the shadow page's gfn. Failure to pre-check the validity of the gfn can lead to an out-of-bounds access to the slot's lpage_info (which typically manifests as a host #PF because the lpage_info is vmalloc'd) if the guest creates a hugepage mapping (in its PTEs) that extends "below" the bounds of a memslot. When faulting in memory for a guest, and the size of the guest mapping is greater than KVM's (current) max mapping, then KVM will create a "direct" shadow page (direct in that there are no gPTEs to shadow, and so the target gfn is a direct calculation given the base gfn of the shadow page). The hugepage recovery flow looks for such direct shadow pages, as forcing 4KiB mappings when dirty logging generates the guest > host mapping size case. When the 4KiB restriction is lifted, then KVM can replace the shadow page with a hugepage. But if KVM originally used a smaller mapping than the guest because the range of memory covered by the guest hugepage exceeds the bounds of a memslot, then KVM will link a direct shadow page with a gfn that is outside the bounds of the memslot being used to fault in memory. The rmap entry added for the leaf mapping is

ELEVATED IMPACT

Severe if exploited (CVSS 8.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 7th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.8CVSS 3.1 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Requires local access to the host
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Linux

Products Linux Linux Kernel

Weakness (CWE)

  • CWE-787: Out-of-bounds Write
  • CWE-125: Out-of-bounds read

CVSS vector

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

References and research data (JSON)

Vendor product assessments

Showing 32 of 581 vendor product statements; 549 omitted. Read the full vendor advisory.

  • kernel-64k-debug-debuginfo-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-devel-matched-0:6.12.0-55.94.1.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • python3-perf-0:6.12.0-55.94.1.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-64k-modules-extra-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-debug-uki-virt-0:6.12.0-55.94.1.el10_0.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-tools-debuginfo-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux BaseOS EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-debug-debuginfo-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • libperf-debuginfo-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-tools-debuginfo-0:6.12.0-55.94.1.el10_0.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-debug-0:6.12.0-55.94.1.el10_0.aarch64 as a component of Red Hat Enterprise Linux Real Time EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • python3-perf-debuginfo-0:6.12.0-55.94.1.el10_0.x86_64 as a component of Red Hat Enterprise Linux Real Time EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Vendor guidance
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-debug-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-debug-modules-extra

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-debug as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-debug

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-zfcpdump-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-modules-extra

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-modules as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-zfcpdump-core as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-core

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-64k-modules as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-64k-modules

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-ipaclones-internal as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-ipaclones-internal

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-64k-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-64k-modules-core

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-selftests-internal as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-selftests-internal

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • rv as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/rv

    • none available: Affected
    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-devel as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-devel

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-kdump as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-kdump

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • bpftool as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/bpftool

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-debug as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-debug

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-kdump as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-kdump

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-debug-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-debug-devel

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-rt-trace as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-trace

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • kernel-tools as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-tools

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00
  • python-perf as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/python-perf

    Red Hat · CVE-2026-63807 · Updated 2026-07-31T14:01:14+00:00

Known Affected Software Configurations

VendorProductVersion range
LinuxLinux Kernel≥ 5.12 and < 5.15.211
LinuxLinux Kernel≥ 5.16 and < 6.1.177
LinuxLinux Kernel≥ 6.2 and < 6.6.144
LinuxLinux Kernel≥ 6.7 and < 6.12.95
LinuxLinux Kernel≥ 6.13 and < 6.18.38
LinuxLinux Kernel≥ 6.19 and < 7.1.3

All CVSS metrics

  • HIGH 8.8 v3.1 · CNA Primary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
  • HIGH 8.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS