CVE-2026-42487

HIGHPre-NVD 7.97.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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 (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Trending — 3 sources updated this week

Also known asEUVD-2026-37888 (ENISA EUVD) · GHSA-xx8x-hq3h-f37h (GitHub Security Advisories)Source: ENISA EUVD

7.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: <0.1%CVSS: 7.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.9HIGHmedium confidence
EG Risk
36
EG Risk 36/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity79% × 45%
Impact severity (EG Severity): CVSS 7.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
<0.1%
EPSS %ILE
below the 1st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.9): severity, escalated by confirmed exploitation. This CVE's 7.9 is its impact severity (EG Severity), not escalated.

EG Severity
7.9 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
<0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

June 18, 2026

Last Modified

June 22, 2026

Advisory Details (3)

Auto-updated Jun 18, 2026
Patch available.
Web page

XSA-491 - Xen Security Advisories

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

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
Web page

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 rangeFix by version rangeDependents
xen—
  • every version up to 4.18.5-r9: fixed in 4.18.5-r9
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • every version up to 4.19.5-r4: fixed in 4.19.5-r4
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • every version up to 4.20.3-r4: fixed in 4.20.3-r4
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • every version up to 4.20.3-r4: fixed in 4.20.3-r4
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • every version up to 4.21.1-r6: fixed in 4.21.1-r6
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.14.2+25-gb6a8c4f72d-2 ... 4.20.3+127-gc42374a105-1 (46 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.17.1+2-gb773c48e36-1 ... 4.17.5+72-g01140da4e8-1 (14 versions)
  • every version up to 4.17.7-0+deb12u1: fixed in 4.17.7-0+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.20.0+68-g35cb38b222-1 ... 4.20.2+7-g1badcf5035-2 (6 versions)
  • every version up to 4.20.3+127-gc42374a105-0+deb13u1: fixed in 4.20.3+127-gc42374a105-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.20.0+68-g35cb38b222-1, 4.20.2+37-g61ff35323e-1, 4.20.2+7-g1badcf5035-1, 4.20.2+7-g1badcf5035-2
  • every version up to 4.20.3+127-gc42374a105-1: fixed in 4.20.3+127-gc42374a105-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 32× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 228 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 128 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-10-26 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  3. 2026-10-25 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  4. 2026-10-25 14:29 UTCEG score recompute
  5. 2026-10-24 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  6. 2026-10-24 06:52 UTCEG score recompute
  7. 2026-10-24 06:52 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  8. 2026-10-22 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  9. 2026-10-20 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  10. 2026-10-18 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  11. 2026-10-18 03:41 UTCEG score recompute
  12. 2026-10-17 14:25 UTCEG score recompute
  13. 2026-10-17 14:25 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  14. 2026-10-16 16:42 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  16. 2026-10-13 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  17. 2026-10-12 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  18. 2026-10-12 16:07 UTCEG score recompute
  19. 2026-10-11 19:49 UTCEG score recompute
  20. 2026-10-11 17:03 UTCEG score recompute
  21. 2026-10-11 14:29 UTCEG score recompute
  22. 2026-10-11 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-10-10 20:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  24. 2026-10-09 20:07 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-10-08 17:12 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
Show 75 more
  1. 2026-10-07 23:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-10-06 15:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  3. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  4. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  9. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  10. 2026-09-20 20:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  11. 2026-09-18 19:28 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  12. 2026-09-17 19:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  13. 2026-09-16 14:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  14. 2026-09-16 05:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-09-14 03:05 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  16. 2026-09-13 13:55 UTCEG score recompute
  17. 2026-09-13 13:55 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  18. 2026-09-11 14:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  19. 2026-09-11 09:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  20. 2026-09-10 09:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  21. 2026-09-08 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  22. 2026-09-07 16:01 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-09-06 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  24. 2026-09-04 05:06 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-09-01 13:54 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  26. 2026-08-30 21:00 UTCEG score recompute
  27. 2026-08-30 21:00 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  28. 2026-08-28 21:41 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  29. 2026-08-27 14:25 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  30. 2026-08-26 14:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  31. 2026-08-25 13:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  32. 2026-08-24 22:19 UTCEG score recompute
  33. 2026-08-24 22:19 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  34. 2026-08-24 05:10 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  35. 2026-08-23 14:11 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  36. 2026-08-23 01:11 UTCEG score recompute
  37. 2026-08-23 01:11 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  38. 2026-08-23 00:19 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  39. 2026-08-21 23:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  40. 2026-08-21 23:21 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  41. 2026-08-21 10:09 UTCEG score recompute
  42. 2026-08-21 10:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  43. 2026-08-20 22:55 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  44. 2026-08-20 21:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  45. 2026-08-20 08:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  46. 2026-08-19 07:43 UTCEG score recompute
  47. 2026-08-19 07:43 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  48. 2026-08-18 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  49. 2026-08-17 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  50. 2026-08-17 09:43 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  51. 2026-08-16 20:44 UTCEG score recompute
  52. 2026-08-16 20:44 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  53. 2026-08-16 14:56 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  54. 2026-08-16 04:59 UTCEG score recompute
  55. 2026-08-16 04:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  56. 2026-08-16 02:14 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  57. 2026-08-15 15:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  58. 2026-08-15 02:59 UTCEG score recompute
  59. 2026-08-15 02:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  60. 2026-08-15 01:30 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  61. 2026-08-14 13:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  62. 2026-08-14 00:58 UTCEG score recompute
  63. 2026-08-14 00:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  64. 2026-08-13 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  65. 2026-08-13 11:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  66. 2026-08-12 22:58 UTCEG score recompute
  67. 2026-08-12 22:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  68. 2026-08-12 13:51 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  69. 2026-08-12 09:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  70. 2026-08-11 20:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  71. 2026-08-11 07:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  72. 2026-08-10 18:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  73. 2026-08-10 05:56 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
  74. 2026-08-09 16:56 UTCEG score recompute
  75. 2026-08-09 16:56 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9

Frequently asked(5)

What is CVE-2026-42487?
CVE-2026-42487 is a high-severity vulnerability; its CVE record was 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 made public?
CVE-2026-42487 was made public on June 9, 2026: that is the date its CVE record's CNA, Xen Project, gives for when the vulnerability was made public. The CVE record itself was published on June 18, 2026. EchelonGraph's copy of the record carries a last-modified date of June 22, 2026; the record at its source may have been updated since.
Is CVE-2026-42487 actively exploited?
CVE-2026-42487 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a <0.1% probability of exploitation in the next 30 days (below the 1st percentile of EPSS-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?
A fix for CVE-2026-42487 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42487 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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