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.
CVE-2026-42487
“—” 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.
Also known asEUVD-2026-37888 (ENISA EUVD) · GHSA-xx8x-hq3h-f37h (GitHub Security Advisories)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.9
- EG Score
- 7.9HIGHmedium confidence
- EG Risk
- 36EG 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, 2026oss-security - Xen Security Advisory 491 v2 (CVE-2026-42487) - x86 HVM I/O port list traversal
http://www.openwall.com/lists/oss-security/2026/06/09/11Vendor 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)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | — |
| — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | — |
| — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | — |
| — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | — |
| — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | — |
| — |
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | 4.14.2+25-gb6a8c4f72d-2 ... 4.20.3+127-gc42374a105-1 (46 versions) |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | 4.17.1+2-gb773c48e36-1 ... 4.17.5+72-g01140da4e8-1 (14 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | 4.20.0+68-g35cb38b222-1 ... 4.20.2+7-g1badcf5035-2 (6 versions) |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| xen | 4.20.0+68-g35cb38b222-1, 4.20.2+37-g61ff35323e-1, 4.20.2+7-g1badcf5035-1, 4.20.2+7-g1badcf5035-2 |
| — |
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.
- 2026-10-27 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-25 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-25 14:29 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-24 06:52 UTCEG score recompute
- 2026-10-24 06:52 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-10-22 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-18 03:41 UTCEG score recompute
- 2026-10-17 14:25 UTCEG score recompute
- 2026-10-17 14:25 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-10-16 16:42 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-12 16:07 UTCEG score recompute
- 2026-10-11 19:49 UTCEG score recompute
- 2026-10-11 17:03 UTCEG score recompute
- 2026-10-11 14:29 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
Show 75 moreShow fewer
- 2026-10-07 23:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.1% · 1st percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-17 19:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-14 03:05 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-09-13 13:55 UTCEG score recompute
- 2026-09-13 13:55 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-09-11 14:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-11 09:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-09-01 13:54 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-30 21:00 UTCEG score recompute
- 2026-08-30 21:00 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-28 21:41 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-25 13:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-24 22:19 UTCEG score recompute
- 2026-08-24 22:19 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-24 05:10 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-23 14:11 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-23 01:11 UTCEG score recompute
- 2026-08-23 01:11 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-23 00:19 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-21 23:21 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-21 10:09 UTCEG score recompute
- 2026-08-21 10:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-20 22:55 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-20 21:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-20 08:09 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-19 07:43 UTCEG score recompute
- 2026-08-19 07:43 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-18 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-17 09:43 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-16 20:44 UTCEG score recompute
- 2026-08-16 20:44 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-16 14:56 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-16 04:59 UTCEG score recompute
- 2026-08-16 04:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-16 02:14 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-15 15:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-15 02:59 UTCEG score recompute
- 2026-08-15 02:59 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-15 01:30 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-14 13:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-14 00:58 UTCEG score recompute
- 2026-08-14 00:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-13 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-13 11:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-12 22:58 UTCEG score recompute
- 2026-08-12 22:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-12 13:51 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
- 2026-08-12 09:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-11 20:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-11 07:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-10 18:58 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-10 05:56 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
- 2026-08-09 16:56 UTCEG score recompute
- 2026-08-09 16:56 UTCGHSA enrichmentGHSA-xx8x-hq3h-f37h · GitHub severity HIGH · GitHub CVSS 7.9
Related CVEs(same product + same CWE)
Same product
10 shownAlpine:v3.20:xen
- CVE-2017-10921EG 10.0CRITICAL
- CVE-2017-10920EG 10.0CRITICAL
- CVE-2017-10918EG 10.0EPSS p90CRITICAL
- CVE-2017-10912EG 10.0CRITICAL
- CVE-2016-9603NVD 5.5EG 9.9EPSS p91CRITICAL
- CVE-2017-2620NVD 5.5EG 9.9CRITICAL
- CVE-2018-12892EG 9.9CRITICAL
- CVE-2025-58143EG 9.8CRITICAL
- CVE-2025-58142EG 9.8CRITICAL
- CVE-2025-27466EG 9.8CRITICAL
Frequently asked(5)
What is CVE-2026-42487?
When was CVE-2026-42487 made public?
Is CVE-2026-42487 actively exploited?
What is the CVSS score of CVE-2026-42487?
How do I remediate CVE-2026-42487?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42487
Is Your Infrastructure Affected by CVE-2026-42487?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.