CVE-2026-31787

NVD 0.07.8▲
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-04-30. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
0.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No confirmed exploitation signals yet
CISA-KEV: Not listedEPSS: 0%CVSS: —Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
—
EG Score
7.8(medium)
EG Risk
—
EPSS
8.2%
KEV
Not listed

Published

April 30, 2026

Last Modified

June 14, 2026

Advisory Details (10)

Auto-updated May 6, 2026
No patch confirmed yet.
generic

XSA-487 - Xen Security Advisories

http://xenbits.xen.org/xsa/advisory-487.html
generic

oss-security - Xen Security Advisory 487 v2 (CVE-2026-31787) - Linux kernel double free in Xen privcmd driver

http://www.openwall.com/lists/oss-security/2026/04/28/14
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a
generic

xen/privcmd: fix double free via VMA splitting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5

Vendor Advisories for CVE-2026-31787(4)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.10.254—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 127 total refreshes for this CVE.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-20 12:02 UTCOSV refresh
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-19 02:29 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-18 10:04 UTCEPSS rescore
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-16 17:03 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 02:00 UTCEPSS rescore
  18. 2026-07-15 02:00 UTCEPSS rescore
  19. 2026-07-13 22:30 UTCEPSS rescore
  20. 2026-07-13 06:13 UTCEPSS rescore
  21. 2026-07-13 06:13 UTCEPSS rescore
  22. 2026-07-12 05:46 UTCEPSS rescore
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 15:15 UTCEPSS rescore
Show 75 more
  1. 2026-07-07 13:46 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 02:30 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-01 15:06 UTCEPSS rescore
  9. 2026-06-30 23:22 UTCEPSS rescore
  10. 2026-06-29 14:06 UTCEPSS rescore
  11. 2026-06-29 14:06 UTCEPSS rescore
  12. 2026-06-28 14:07 UTCEPSS rescore
  13. 2026-06-28 14:07 UTCEPSS rescore
  14. 2026-06-28 04:56 UTCEPSS rescore
  15. 2026-06-28 04:56 UTCEPSS rescore
  16. 2026-06-27 03:08 UTCEPSS rescore
  17. 2026-06-25 13:49 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-23 21:33 UTCEPSS rescore
  22. 2026-06-22 14:25 UTCEPSS rescore
  23. 2026-06-22 14:25 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 14:56 UTCEPSS rescore
  26. 2026-06-21 01:59 UTCEPSS rescore
  27. 2026-06-19 19:25 UTCEPSS rescore
  28. 2026-06-19 19:25 UTCEPSS rescore
  29. 2026-06-18 17:52 UTCEPSS rescore
  30. 2026-06-18 17:52 UTCEPSS rescore
  31. 2026-06-17 17:53 UTCEPSS rescore
  32. 2026-06-16 17:52 UTCEPSS rescore
  33. 2026-06-15 17:49 UTCEPSS rescore
  34. 2026-06-14 23:28 UTCMITRE cvelistV5
  35. 2026-06-14 23:18 UTCEPSS rescore
  36. 2026-06-14 21:51 UTCGHSA enrichment
  37. 2026-06-14 09:18 UTCGHSA enrichment
  38. 2026-06-13 23:00 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-12 06:03 UTCGHSA enrichment
  42. 2026-06-11 17:30 UTCGHSA enrichment
  43. 2026-06-11 14:00 UTCEPSS rescore
  44. 2026-06-11 04:58 UTCGHSA enrichment
  45. 2026-06-10 22:18 UTCEPSS rescore
  46. 2026-06-10 13:22 UTCEPSS rescore
  47. 2026-06-10 13:22 UTCGHSA enrichment
  48. 2026-06-10 00:50 UTCGHSA enrichment
  49. 2026-06-09 12:18 UTCGHSA enrichment
  50. 2026-06-08 23:45 UTCGHSA enrichment
  51. 2026-06-08 14:17 UTCEPSS rescore
  52. 2026-06-08 14:17 UTCEPSS rescore
  53. 2026-06-08 06:03 UTCGHSA enrichment
  54. 2026-06-07 17:30 UTCGHSA enrichment
  55. 2026-06-07 15:25 UTCEPSS rescore
  56. 2026-06-07 15:25 UTCEPSS rescore
  57. 2026-06-07 15:25 UTCEPSS rescore
  58. 2026-06-07 04:58 UTCGHSA enrichment
  59. 2026-06-06 16:26 UTCGHSA enrichment
  60. 2026-06-06 13:47 UTCEPSS rescore
  61. 2026-06-06 13:47 UTCEPSS rescore
  62. 2026-06-06 03:44 UTCGHSA enrichment
  63. 2026-06-05 22:47 UTCEPSS rescore
  64. 2026-06-05 22:47 UTCEPSS rescore
  65. 2026-06-05 15:00 UTCGHSA enrichment
  66. 2026-06-05 02:28 UTCGHSA enrichment
  67. 2026-06-04 13:56 UTCGHSA enrichment
  68. 2026-06-04 13:12 UTCEPSS rescore
  69. 2026-06-04 13:12 UTCEPSS rescore
  70. 2026-06-04 01:24 UTCGHSA enrichment
  71. 2026-06-03 12:50 UTCGHSA enrichment
  72. 2026-06-03 00:17 UTCGHSA enrichment
  73. 2026-06-02 20:13 UTCEPSS rescore
  74. 2026-06-02 20:13 UTCEPSS rescore
  75. 2026-06-02 11:44 UTCGHSA enrichment

Frequently asked(4)

What is CVE-2026-31787?
CVE-2026-31787 is a publicly disclosed vulnerability published on April 30, 2026. In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: fix double free via VMA splitting privcmdvmops defines .close (privcmdclose), but neither .maysplit nor .open. When userspace does a partial munmap() on a privcmd mapping, the kernel splits the VMA via splitvma().…
When was CVE-2026-31787 disclosed?
CVE-2026-31787 was first published in the National Vulnerability Database on April 30, 2026, with the most recent update on June 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31787 actively exploited?
CVE-2026-31787 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 8.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
How do I remediate CVE-2026-31787?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31787, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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