CVE-2026-31787

Aliases:UBUNTU-CVE-2026-31787DEBIAN-CVE-2026-31787CGA-22hj-qx3f-vrxjCGA-3j87-9h3x-crg3CGA-4hwh-fpgp-w8pfCGA-6mqx-3876-f974CGA-8jx9-p7q9-85m6CGA-8x89-q8h2-wpwgCGA-94pc-7rj4-gq8qCGA-cjf6-w94r-vq88CGA-jhx2-h5wm-hv2pCGA-v7qp-97wg-r84xCGA-w97g-g4p5-5fg2CGA-wv23-rv67-xpgx
Advisory lineage Upstream: 0 Downstream: 20
Analyzed
Published: 30 Apr 2026, 10:31
Last modified:14 Jun 2026, 17:44

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (nvd)
EPSS Score
0.18% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

30 Apr 2026, 10:31
Published
Vulnerability first disclosed
14 Jun 2026, 17:44
Last Modified
Vulnerability information updated

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 Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.18%• Percentile: 8%

Techniques & Countermeasures

  • CWE-415•Double Free

    The product calls free() twice on the same memory address.

Affected Systems

  • chainguard•linux-aws-6.12

    < 6.12.85-r2

  • chainguard•linux-aws-6.18

    < 6.18.31-r0

  • chainguard•linux-azure-6.12

    < 6.12.85-r2

  • chainguard•linux-azure-6.18

    < 6.18.24-r1 | < 6.18.31-r0

  • chainguard•linux-gcp-6.12

    < 6.12.89-r0

  • chainguard•linux-gcp-6.18

    < 6.18.31-r0

  • chainguard•linux-qemu-6.12

    < 6.12.89-r0

  • chainguard•linux-qemu-6.18

    < 6.18.24-r3

  • chainguard•linux-qemu-rc

    < 7.1_rc3-r0

  • chainguard•linux-vmware-6.12

    < 6.12.85-r2

  • chainguard•linux-vmware-6.18

    < 6.18.31-r0

  • debian•linux

    < 5.10.257-1 | < 6.1.170-1 | < 6.12.85-1 | < 7.0.3-1

  • debian•linux-6.1

    < 6.1.170-1~deb11u1

  • ubuntu•linux

    all | all | all | all | all

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | all | all | all | all

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    all

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    all

  • ubuntu•linux-aws-6.17

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    all

  • ubuntu•linux-aws-7.0

    all

  • ubuntu•linux-aws-fips

    all

  • ubuntu•linux-aws-hwe

    all

  • ubuntu•linux-azure

    all | all | all | all | all | all

  • ubuntu•linux-azure-4.15

    all

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    all

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.14

    all

  • ubuntu•linux-azure-6.17

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    all

  • ubuntu•linux-azure-7.0

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | all | all | all

Showing first 50 affected entries in server-rendered view.

References (14)