CVE-2026-63807: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-xxf6-pvjr-qhj4
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CVSS 8.8
CWE-125 CWE-787
Published
Advisory Summary

CVE-2026-63807 is a HIGH (CVSS 8.8) security vulnerability vulnerability (CWE-125: Out-of-bounds Read) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product reads data past the end, or before the beginning, of the intended buffer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63807 at a Glance

CVE Identifier CVE-2026-63807
GHSA Identifier GHSA-xxf6-pvjr-qhj4
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-63807

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-63807, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-125: Out-of-bounds Read, where the product reads data past the end, or before the beginning, of the intended buffer. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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 correct and within bounds, but the gfn of the leaf SPTE's parent shadow page will be out of bounds. BUG: unable to handle page fault for address: ffffc90000806ffc #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 100000067 P4D 100000067 PUD 1002a7067 PMD 10612f067 PTE 0 Oops: Oops: 0000 [#1] SMP CPU: 13 UID: 1000 PID: 757 Comm: mmu_stress_test Not tainted 7.1.0-rc1-48ce1e26eace-x86_pir_to_irr_comments-vm #341 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kvm_mmu_max_mapping_level+0x79/0x2b0 [kvm] Call Trace: <TASK> kvm_mmu_recover_huge_pages+0x21b/0x320 [kvm] kvm_set_memslot+0x1ee/0x590 [kvm] kvm_set_memory_region.part.0+0x3a1/0x4d0 [kvm] kvm_vm_ioctl+0x9bf/0x15d0 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb7/0xbb0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f21c0f1a9bf </TASK> Don't bother pre-checking the bounds of the potential hugepage, i.e. don't check that e.g. sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level + 1) is also within the memslot, as the checks performed by kvm_mmu_max_mapping_level() are a superset of the basic bounds checks. I.e. pre-checking the full range would be a dubious micro-optimization.

References

NVD — CVE-2026-63807 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63807
git.kernel.org/stable/c/18587f9831... WEB
https://git.kernel.org/stable/c/18587f9831612e24cd8f24be1ec15478feff7abc
git.kernel.org/stable/c/48b91ed7e2... WEB
https://git.kernel.org/stable/c/48b91ed7e22bb82571c34f8b80b6ecdc90a6fab8
git.kernel.org/stable/c/5cab1c989f... WEB
https://git.kernel.org/stable/c/5cab1c989f938f5e1b9a0de66486f1fc2c28479b
git.kernel.org/stable/c/7b52008023... WEB
https://git.kernel.org/stable/c/7b52008023b7facf40fba3ebe92449bda8ea53b9
git.kernel.org/stable/c/b2ae3245ea... WEB
https://git.kernel.org/stable/c/b2ae3245ea44dccaa9af676b6747476951883318
git.kernel.org/stable/c/c5c29b3c26... WEB
https://git.kernel.org/stable/c/c5c29b3c268332afe67d598a034c58344540ed92
git.kernel.org/stable/c/ef057cbf82... WEB
https://git.kernel.org/stable/c/ef057cbf825e03b63f6edf5980f96abf3c53089d

Frequently Asked Questions

What is CVE-2026-63807?
CVE-2026-63807 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-125: Out-of-bounds Read.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63807?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-63807?
CVE-2026-63807 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-63807?
CVE-2026-63807 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check Maven dependencies for CVE-2026-63807?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xxf6-pvjr-qhj4",
  "modified" : "2026-07-20T15:31:47Z",
  "published" : "2026-07-19T12:30:23Z",
  "aliases" : [ "CVE-2026-63807" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level\n\nWhen recovering hugepages in the shadow MMU, verify that the base gfn of\nthe shadow page is actually contained within the target memslot, *before*\nquerying the max mapping level given the shadow page's gfn.  Failure to\npre-check the validity of the gfn can lead to an out-of-bounds access to\nthe slot's lpage_info (which typically manifests as a host #PF because the\nlpage_info is vmalloc'd) if the guest creates a hugepage mapping (in its\nPTEs) that extends \"below\" the bounds of a memslot.\n\nWhen faulting in memory for a guest, and the size of the guest mapping is\ngreater than KVM's (current) max mapping, then KVM will create a \"direct\"\nshadow page (direct in that there are no gPTEs to shadow, and so the target\ngfn is a direct calculation given the base gfn of the shadow page).  The\nhugepage recovery flow looks for such direct shadow pages, as forcing 4KiB\nmappings when dirty logging generates the guest > host mapping size case.\nWhen the 4KiB restriction is lifted, then KVM can replace the shadow page\nwith a hugepage.\n\nBut if KVM originally used a smaller mapping than the guest because the\nrange of memory covered by the guest hugepage exceeds the bounds of a\nmemslot, then KVM will link a direct shadow page with a gfn that is outside\nthe bounds of the memslot being used to fault in memory.  The rmap entry\nadded for the leaf mapping is correct and within bounds, but the gfn of the\nleaf SPTE's parent shadow page will be out of bounds.\n\n  BUG: unable to handle page fault for address: ffffc90000806ffc\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  PGD 100000067 P4D 100000067 PUD 1002a7067 PMD 10612f067 PTE 0\n  Oops: Oops: 0000 [#1] SMP\n  CPU: 13 UID: 1000 PID: 757 Comm: mmu_stress_test Not tainted 7.1.0-rc1-48ce1e26eace-x86_pir_to_irr_comments-vm #341 PREEMPT\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:kvm_mmu_max_mapping_level+0x79/0x2b0 [kvm]\n  Call Trace:\n   <TASK>\n   kvm_mmu_recover_huge_pages+0x21b/0x320 [kvm]\n   kvm_set_memslot+0x1ee/0x590 [kvm]\n   kvm_set_memory_region.part.0+0x3a1/0x4d0 [kvm]\n   kvm_vm_ioctl+0x9bf/0x15d0 [kvm]\n   __x64_sys_ioctl+0x8a/0xd0\n   do_syscall_64+0xb7/0xbb0\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n  RIP: 0033:0x7f21c0f1a9bf\n   </TASK>\n\nDon't bother pre-checking the bounds of the potential hugepage, i.e. don't\ncheck that e.g. sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level + 1) is also\nwithin the memslot, as the checks performed by kvm_mmu_max_mapping_level()\nare a superset of the basic bounds checks.  I.e. pre-checking the full\nrange would be a dubious micro-optimization.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-63807"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/18587f9831612e24cd8f24be1ec15478feff7abc"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/48b91ed7e22bb82571c34f8b80b6ecdc90a6fab8"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/5cab1c989f938f5e1b9a0de66486f1fc2c28479b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/7b52008023b7facf40fba3ebe92449bda8ea53b9"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b2ae3245ea44dccaa9af676b6747476951883318"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c5c29b3c268332afe67d598a034c58344540ed92"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/ef057cbf825e03b63f6edf5980f96abf3c53089d"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-125", "CWE-787" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-19T12:16:53Z"
  }
}