CVE-2025-27466

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2025-09-11. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2025-28913 (ENISA EUVD) · GHSA-wx7g-7g56-c87j (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]

There are multiple issues related to the handling and accessing of guest memory pages in the viridian code:

  • A NULL pointer dereference in the updating of the reference TSC area.
This is CVE-2025-27466.
  • A NULL pointer dereference by assuming the SIM page is mapped when
a synthetic timer message has to be delivered. This is CVE-2025-58142.
  • A race in the mapping of the reference TSC page, where a guest can
get Xen to free a page while still present in the guest physical to machine (p2m) page tables. This is CVE-2025-58143.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
43rd
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

September 11, 2025

Last Modified

October 19, 2026

Advisory Details (3)

Auto-updated Nov 7, 2026
Patch available.
Web page

XSA-472 - Xen Security Advisories

http://xenbits.xen.org/xsa/advisory-472.html
Web page

oss-security - Xen Security Advisory 472 v2 (CVE-2025-27466,CVE-2025-58142,CVE-2025-58143) - Mutiple vulnerabilities in the Viridian interface

http://www.openwall.com/lists/oss-security/2025/09/09/1
Web page

XSA-472 - Xen Security Advisories

https://xenbits.xenproject.org/xsa/advisory-472.html

Affected Packages

(10 across 10 ecosystems)
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.18.5-r2: fixed in 4.18.5-r2
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.18.5-r2: fixed in 4.18.5-r2
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.19.3-r1: fixed in 4.19.3-r1
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.20.1-r1: fixed in 4.20.1-r1
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.20.1-r1: fixed in 4.20.1-r1
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
xen—
  • 4.13.0 up to 4.20.1-r1: fixed in 4.20.1-r1
—
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+23-ga4e5191dc0-1+deb12u1 (13 versions)
  • every version up to 4.17.5+72-g01140da4e8-1: fixed in 4.17.5+72-g01140da4e8-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.20.0+68-g35cb38b222-1
  • every version up to 4.20.2+7-g1badcf5035-0+deb13u1: fixed in 4.20.2+7-g1badcf5035-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
xen4.20.0+68-g35cb38b222-1
  • every version up to 4.20.2+7-g1badcf5035-1: fixed in 4.20.2+7-g1badcf5035-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 64× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 268 rows 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 168 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:49 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  2. 2026-11-13 16:49 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-12 18:16 UTCEchelonGraph re-scored
  4. 2026-11-12 18:16 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-11-12 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  6. 2026-11-11 20:19 UTCEchelonGraph re-scored
  7. 2026-11-11 20:19 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-11-11 16:36 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  9. 2026-11-10 22:23 UTCEchelonGraph re-scored
  10. 2026-11-10 22:23 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-11-10 16:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-11-10 00:08 UTCEchelonGraph re-scored
  13. 2026-11-10 00:08 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-11-09 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  15. 2026-11-09 02:12 UTCEchelonGraph re-scored
  16. 2026-11-09 02:12 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-11-08 16:36 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-11-08 04:16 UTCEchelonGraph re-scored
  19. 2026-11-08 04:16 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-11-07 16:36 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-11-07 06:14 UTCEchelonGraph re-scored
  22. 2026-11-07 06:14 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-11-06 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-11-06 08:18 UTCEchelonGraph re-scored
  25. 2026-11-06 08:18 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 more
  1. 2026-11-05 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  2. 2026-11-05 10:55 UTCOSV refresh
  3. 2026-11-05 10:22 UTCEchelonGraph re-scored
  4. 2026-11-05 10:22 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-11-04 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  6. 2026-11-04 12:23 UTCEchelonGraph re-scored
  7. 2026-11-04 12:23 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-11-03 16:44 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  9. 2026-11-03 14:27 UTCEchelonGraph re-scored
  10. 2026-11-03 14:27 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-11-02 16:42 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  12. 2026-11-02 16:14 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-11-01 18:10 UTCEchelonGraph re-scored
  14. 2026-11-01 18:10 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-11-01 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  16. 2026-10-31 20:14 UTCEchelonGraph re-scored
  17. 2026-10-31 20:14 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  19. 2026-10-30 22:19 UTCEchelonGraph re-scored
  20. 2026-10-30 22:19 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-30 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  22. 2026-10-30 00:21 UTCEchelonGraph re-scored
  23. 2026-10-30 00:21 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-29 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  25. 2026-10-29 02:26 UTCEchelonGraph re-scored
  26. 2026-10-29 02:26 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  27. 2026-10-28 16:30 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  28. 2026-10-28 04:28 UTCEchelonGraph re-scored
  29. 2026-10-28 04:28 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  30. 2026-10-27 16:30 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  31. 2026-10-27 06:29 UTCEchelonGraph re-scored
  32. 2026-10-27 06:29 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  33. 2026-10-26 16:29 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  34. 2026-10-26 04:38 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-25 16:38 UTCEchelonGraph re-scored
  36. 2026-10-25 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  37. 2026-10-25 06:42 UTCEchelonGraph re-scored
  38. 2026-10-25 06:42 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-10-24 16:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  40. 2026-10-24 08:47 UTCEchelonGraph re-scored
  41. 2026-10-24 08:47 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-23 16:30 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  43. 2026-10-23 10:51 UTCEchelonGraph re-scored
  44. 2026-10-23 10:51 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-22 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  46. 2026-10-22 12:51 UTCEchelonGraph re-scored
  47. 2026-10-22 12:51 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  48. 2026-10-21 16:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  49. 2026-10-21 14:54 UTCEchelonGraph re-scored
  50. 2026-10-21 14:54 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  52. 2026-10-20 16:12 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-10-19 17:29 UTCEchelonGraph re-scored
  54. 2026-10-19 17:29 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-10-19 16:30 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  56. 2026-10-19 08:59 UTCEchelonGraph re-scored
  57. 2026-10-19 08:59 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-10-18 16:30 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  59. 2026-10-18 10:59 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-10-18 05:41 UTCEchelonGraph re-scored
  61. 2026-10-17 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  62. 2026-10-17 13:02 UTCEchelonGraph re-scored
  63. 2026-10-17 13:02 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-10-16 16:38 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  65. 2026-10-16 15:04 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-10-15 17:07 UTCEchelonGraph re-scored
  67. 2026-10-15 17:07 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  68. 2026-10-15 16:30 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  69. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  70. 2026-10-14 11:06 UTCEchelonGraph re-scored
  71. 2026-10-14 11:06 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-10-13 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  73. 2026-10-13 09:47 UTCGHSA enrichmentGHSA-wx7g-7g56-c87j · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-10-12 17:14 UTCEchelonGraph re-scored
  75. 2026-10-12 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile

Frequently asked(5)

What is CVE-2025-27466?
CVE-2025-27466 is a critical-severity vulnerability; its CVE record was published on September 11, 2025. [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] There are multiple issues related to the handling and accessing of guest memory pages in the viridian code: 1. A NULL pointer dereference in the updating of the reference…
When was CVE-2025-27466 made public?
CVE-2025-27466 was made public on September 9, 2025: 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 September 11, 2025. EchelonGraph's copy of the record carries a last-modified date of October 19, 2026; the record at its source may have been updated since.
Is CVE-2025-27466 actively exploited?
CVE-2025-27466 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (43rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-27466?
CVE-2025-27466 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2025-27466?
A fix for CVE-2025-27466 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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