CVE-2026-31787

HIGH EPSS 8.1%
Published Apr 30, 20262mo ago · Modified Jun 17, 20261w ago
7.8 CVSS 3.1
High
Find Similar
Published Apr 30, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: fix double free via VMA splitting privcmd_vm_ops defines .close (privcmd_close), but neither .may_split nor .open. When userspace does a partial munmap() on a privcmd mapping, the kernel splits the VMA via __split_vma(). Since may_split is NULL, the split is allowed. vm_area_dup() copies vm_private_data (a pages array allocated in alloc_empty_pages()) into the new VMA without any fixup, because there is no .open callback. Both VMAs now point to the same pages array. When the unmapped portion is closed, privcmd_close() calls: - xen_unmap_domain_gfn_range() - xen_free_unpopulated_pages() - kvfree(pages) The surviving VMA still holds the dangling pointer. When it is later destroyed, the same sequence runs again, which leads to a double free. Fix this issue by adding a .may_split callback denying the VMA split. This is XSA-487 / CVE-2026-31787

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
8.1% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-415

Affected Products 9

VendorProductVersionRange
linuxlinux_kernel*≥3.8  –  <5.10.254
linuxlinux_kernel*≥5.11  –  <5.15.204
linuxlinux_kernel*≥5.16  –  <6.1.170
linuxlinux_kernel*≥6.2  –  <6.6.137
linuxlinux_kernel*≥6.7  –  <6.12.85
linuxlinux_kernel*≥6.13  –  <6.18.26
linuxlinux_kernel*≥6.19  –  <7.0.3
linuxlinux_kernel7.1any
linuxlinux_kernel7.1any

References 10

  • openwall.com http://www.openwall.com/lists/oss-security/2026/04/28/14
    Mailing ListThird Party Advisory
  • xenbits.xen.org http://xenbits.xen.org/xsa/advisory-487.html
    Third Party Advisory
  • git.kernel.org https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4
    Patch