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
7.9
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.9Exploit: NoneExposed: 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
0.8%
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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 68× 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.

  1. 2026-07-24 14:17 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:11 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-21 15:24 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-18 10:04 UTCEPSS rescore
  9. 2026-07-16 21:01 UTCGHSA enrichment
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-16 04:50 UTCGHSA enrichment
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-15 15:50 UTCGHSA enrichment
  14. 2026-07-15 02:50 UTCGHSA enrichment
  15. 2026-07-15 02:00 UTCEPSS rescore
  16. 2026-07-14 13:34 UTCGHSA enrichment
  17. 2026-07-14 00:32 UTCGHSA enrichment
  18. 2026-07-13 22:30 UTCEPSS rescore
  19. 2026-07-13 11:32 UTCGHSA enrichment
  20. 2026-07-13 06:13 UTCEPSS rescore
  21. 2026-07-12 22:32 UTCGHSA enrichment
  22. 2026-07-12 09:30 UTCGHSA enrichment
  23. 2026-07-12 05:46 UTCEPSS rescore
  24. 2026-07-11 20:30 UTCGHSA enrichment
  25. 2026-07-11 08:27 UTCEPSS rescore
Show 57 more
  1. 2026-07-11 07:30 UTCGHSA enrichment
  2. 2026-07-10 18:30 UTCGHSA enrichment
  3. 2026-07-10 05:24 UTCGHSA enrichment
  4. 2026-07-09 19:10 UTCEPSS rescore
  5. 2026-07-09 16:12 UTCGHSA enrichment
  6. 2026-07-09 02:21 UTCGHSA enrichment
  7. 2026-07-08 15:15 UTCEPSS rescore
  8. 2026-07-08 13:17 UTCGHSA enrichment
  9. 2026-07-08 00:15 UTCGHSA enrichment
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-07 11:14 UTCGHSA enrichment
  12. 2026-07-06 21:39 UTCGHSA enrichment
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 16:27 UTCEPSS rescore
  15. 2026-07-06 06:27 UTCGHSA enrichment
  16. 2026-07-05 17:20 UTCGHSA enrichment
  17. 2026-07-05 04:19 UTCGHSA enrichment
  18. 2026-07-05 02:30 UTCEPSS rescore
  19. 2026-07-04 15:10 UTCGHSA enrichment
  20. 2026-07-04 06:31 UTCEPSS rescore
  21. 2026-07-04 02:09 UTCGHSA enrichment
  22. 2026-07-03 13:08 UTCGHSA enrichment
  23. 2026-07-03 00:09 UTCGHSA enrichment
  24. 2026-07-02 11:08 UTCGHSA enrichment
  25. 2026-07-01 21:34 UTCGHSA enrichment
  26. 2026-07-01 08:33 UTCGHSA enrichment
  27. 2026-06-30 23:22 UTCEPSS rescore
  28. 2026-06-30 19:33 UTCGHSA enrichment
  29. 2026-06-30 06:33 UTCGHSA enrichment
  30. 2026-06-29 17:31 UTCGHSA enrichment
  31. 2026-06-29 14:06 UTCEPSS rescore
  32. 2026-06-29 04:31 UTCGHSA enrichment
  33. 2026-06-28 15:28 UTCGHSA enrichment
  34. 2026-06-28 14:07 UTCEPSS rescore
  35. 2026-06-28 04:56 UTCEPSS rescore
  36. 2026-06-28 02:28 UTCGHSA enrichment
  37. 2026-06-27 13:28 UTCGHSA enrichment
  38. 2026-06-27 03:08 UTCEPSS rescore
  39. 2026-06-27 00:27 UTCGHSA enrichment
  40. 2026-06-26 11:26 UTCGHSA enrichment
  41. 2026-06-25 22:22 UTCGHSA enrichment
  42. 2026-06-25 13:49 UTCEPSS rescore
  43. 2026-06-25 13:49 UTCEPSS rescore
  44. 2026-06-25 09:21 UTCGHSA enrichment
  45. 2026-06-24 20:21 UTCGHSA enrichment
  46. 2026-06-24 14:05 UTCEPSS rescore
  47. 2026-06-24 07:20 UTCGHSA enrichment
  48. 2026-06-23 21:33 UTCEPSS rescore
  49. 2026-06-23 18:17 UTCGHSA enrichment
  50. 2026-06-23 05:16 UTCGHSA enrichment
  51. 2026-06-22 16:15 UTCGHSA enrichment
  52. 2026-06-22 03:05 UTCGHSA enrichment
  53. 2026-06-21 13:44 UTCEG score recompute▲ 7.90
  54. 2026-06-21 13:43 UTCGHSA enrichment
  55. 2026-06-18 17:22 UTCNVD updateCVSS v3 → 7.9 · severity → HIGH
  56. 2026-06-18 15:45 UTCEG score recompute
  57. 2026-06-18 15:45 UTCGHSA enrichment

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 0.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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

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