CVE-2026-42487

HIGHPre-NVD 7.97.9—
EchelonGraph scoreMEDIUM confidence

Score 7.9 from GitHub Security Advisory (severity: HIGH) published 2026-06-18. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
7.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.9Exploit: None knownExposed: 0

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

HVM guest I/O port accesses are subject to either emulation or at least translation. Translations are managed by the device model (via XEN_DOMCTL_ioport_mapping), and hence the linked list used may changed at any time. Traversal of those lists (while handling guest I/O port accesses) therefore needs synchronizing with updates, which was missing so far.

CVSS v3
7.9
EG Score
7.9(medium)
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
Severity79% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

June 18, 2026

Last Modified

June 22, 2026

Advisory Details (3)

Auto-updated Jun 18, 2026
No patch confirmed yet.
generic

XSA-491 - Xen Security Advisories

http://xenbits.xen.org/xsa/advisory-491.html
generic

oss-security - Xen Security Advisory 491 v2 (CVE-2026-42487) - x86 HVM I/O port list traversal

http://www.openwall.com/lists/oss-security/2026/06/09/11
generic

XSA-491 - Xen Security Advisories

https://xenbits.xenproject.org/xsa/advisory-491.html

Vendor Advisories for CVE-2026-42487(1)

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

Affected Packages

(9 across 9 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
xen—4.18.5-r9—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
xen—4.19.5-r4—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
xen—4.20.3-r4—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
xen—4.20.3-r4—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
xen—4.21.1-r6—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
xen4.14.2+25-gb6a8c4f72d-2 ... 4.20.3+127-gc42374a105-1 (46 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
xen4.17.1+2-gb773c48e36-1 ... 4.20.3+127-gc42374a105-1 (25 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
xen4.20.0+68-g35cb38b222-1 ... 4.20.2+7-g1badcf5035-2 (6 versions)4.20.3+127-gc42374a105-0+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
xen4.20.0+68-g35cb38b222-1, 4.20.2+37-g61ff35323e-1, 4.20.2+7-g1badcf5035-1, 4.20.2+7-g1badcf5035-24.20.3+127-gc42374a105-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 50× 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 186 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-42487?
CVE-2026-42487 is a high vulnerability published on June 18, 2026. HVM guest I/O port accesses are subject to either emulation or at least translation. Translations are managed by the device model (via XENDOMCTLioport_mapping), and hence the linked list used may changed at any time. Traversal of those lists (while handling guest I/O port accesses) therefore needs…
When was CVE-2026-42487 disclosed?
CVE-2026-42487 was first published in the National Vulnerability Database on June 18, 2026, with the most recent update on June 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42487 actively exploited?
CVE-2026-42487 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 99.3% of all scored CVEs.
What is the CVSS score of CVE-2026-42487?
CVE-2026-42487 has a CVSS v3.1 base score of 7.9 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-42487?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42487, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42487

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