CVE-2026-31787

HIGHCVSS · not yet scored7.8
EchelonGraph scoreLOW confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-04-30.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

A fix is available — apply it.

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(low)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
8%
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(11)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:4.18.0-372.206.1.el8_62026-08-12redhat
redhatkernel-0:4.18.0-477.158.1.el8_82026-08-10redhat
redhatkernel-0:6.12.0-55.95.1.el10_02026-08-10redhat
redhatkernel-rt-0:5.14.0-284.186.1.rt14.471.el9_22026-08-07redhat
redhatkernel-0:5.14.0-284.186.1.el9_22026-08-07redhat
redhatkernel-0:5.14.0-427.141.1.el9_42026-07-31redhat
redhatkernel-0:4.18.0-305.200.1.el8_42026-07-28redhat
redhatkernel-0:5.14.0-687.17.1.el9_82026-06-22redhat
redhatkernel-0:6.12.0-211.26.1.el10_22026-06-20redhat
redhatkernel-rt-0:4.18.0-553.134.1.rt7.475.el8_102026-06-16redhat
redhatkernel-0:4.18.0-553.134.1.el8_102026-06-16redhat
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.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (53 versions)5.10.257-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.1-1~exp1 (132 versions)7.0.3-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 32× 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 232 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(4)

What is CVE-2026-31787?
CVE-2026-31787 is a high 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 0% probability of exploitation in the next 30 days, which ranks it in the top 91.9% of all scored CVEs.
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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