CVE-2026-31397: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-6fhq-5hrr-wq44
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CVSS 7.8
CWE-476
Published
Advisory Summary

CVE-2026-31397 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-476: NULL Pointer Dereference) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product dereferences a pointer that it expects to be valid but is null.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-31397 at a Glance

CVE Identifier CVE-2026-31397
GHSA Identifier GHSA-6fhq-5hrr-wq44
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-476: NULL Pointer Dereference
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.8

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:U/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 Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-31397

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-2026-31397, 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-476: NULL Pointer Dereference, where the product dereferences a pointer that it expects to be valid but is null. 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: mm/huge_memory: fix use of NULL folio in move_pages_huge_pmd() move_pages_huge_pmd() handles UFFDIO_MOVE for both normal THPs and huge zero pages. For the huge zero page path, src_folio is explicitly set to NULL, and is used as a sentinel to skip folio operations like lock and rmap. In the huge zero page branch, src_folio is NULL, so folio_mk_pmd(NULL, pgprot) passes NULL through folio_pfn() and page_to_pfn(). With SPARSEMEM_VMEMMAP this silently produces a bogus PFN, installing a PMD pointing to non-existent physical memory. On other memory models it is a NULL dereference. Use page_folio(src_page) to obtain the valid huge zero folio from the page, which was obtained from pmd_page() and remains valid throughout. After commit d82d09e48219 ("mm/huge_memory: mark PMD mappings of the huge zero folio special"), moved huge zero PMDs must remain special so vm_normal_page_pmd() continues to treat them as special mappings. move_pages_huge_pmd() currently reconstructs the destination PMD in the huge zero page branch, which drops PMD state such as pmd_special() on architectures with CONFIG_ARCH_HAS_PTE_SPECIAL. As a result, vm_normal_page_pmd() can treat the moved huge zero PMD as a normal page and corrupt its refcount. Instead of reconstructing the PMD from the folio, derive the destination entry from src_pmdval after pmdp_huge_clear_flush(), then handle the PMD metadata the same way move_huge_pmd() does for moved entries by marking it soft-dirty and clearing uffd-wp.

References

NVD — CVE-2026-31397 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31397
git.kernel.org/stable/c/e3133d0986... WEB
https://git.kernel.org/stable/c/e3133d0986dc5a231d5419167dbac65312b28b41
git.kernel.org/stable/c/f3caaee0f9... WEB
https://git.kernel.org/stable/c/f3caaee0f9e489fd2282d4ce45791dc8aed2da62
git.kernel.org/stable/c/fae654083b... WEB
https://git.kernel.org/stable/c/fae654083bfa409bb2244f390232e2be47f05bfc

Frequently Asked Questions

What is CVE-2026-31397?
CVE-2026-31397 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-476: NULL Pointer Dereference.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-31397?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-31397?
CVE-2026-31397 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-31397?
CVE-2026-31397 is classified under CWE-476: NULL Pointer Dereference (The product dereferences a pointer that it expects to be valid but is NULL.).
How can I check Maven dependencies for CVE-2026-31397?
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 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-6fhq-5hrr-wq44",
  "modified" : "2026-04-27T15:30:32Z",
  "published" : "2026-04-03T18:31:23Z",
  "aliases" : [ "CVE-2026-31397" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: fix use of NULL folio in move_pages_huge_pmd()\n\nmove_pages_huge_pmd() handles UFFDIO_MOVE for both normal THPs and huge\nzero pages.  For the huge zero page path, src_folio is explicitly set to\nNULL, and is used as a sentinel to skip folio operations like lock and\nrmap.\n\nIn the huge zero page branch, src_folio is NULL, so folio_mk_pmd(NULL,\npgprot) passes NULL through folio_pfn() and page_to_pfn().  With\nSPARSEMEM_VMEMMAP this silently produces a bogus PFN, installing a PMD\npointing to non-existent physical memory.  On other memory models it is a\nNULL dereference.\n\nUse page_folio(src_page) to obtain the valid huge zero folio from the\npage, which was obtained from pmd_page() and remains valid throughout.\n\nAfter commit d82d09e48219 (\"mm/huge_memory: mark PMD mappings of the huge\nzero folio special\"), moved huge zero PMDs must remain special so\nvm_normal_page_pmd() continues to treat them as special mappings.\n\nmove_pages_huge_pmd() currently reconstructs the destination PMD in the\nhuge zero page branch, which drops PMD state such as pmd_special() on\narchitectures with CONFIG_ARCH_HAS_PTE_SPECIAL.  As a result,\nvm_normal_page_pmd() can treat the moved huge zero PMD as a normal page\nand corrupt its refcount.\n\nInstead of reconstructing the PMD from the folio, derive the destination\nentry from src_pmdval after pmdp_huge_clear_flush(), then handle the PMD\nmetadata the same way move_huge_pmd() does for moved entries by marking it\nsoft-dirty and clearing uffd-wp.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31397"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e3133d0986dc5a231d5419167dbac65312b28b41"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/f3caaee0f9e489fd2282d4ce45791dc8aed2da62"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/fae654083bfa409bb2244f390232e2be47f05bfc"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-476" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-04-03T16:16:38Z"
  }
}