CVE-2026-66395

CRITICALPre-NVD 9.69.6
EchelonGraph scoreMEDIUM confidence

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

Score 9.6 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-27. A secondary CVSS source baseline 9.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Elevated

Also known asEUVD-2026-49328 (ENISA EUVD) · GHSA-x52j-m89g-wh64 (GitHub Security Advisories)Source: ENISA EUVD

9.6EG
EchelonGraph verdictPlan mitigationNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.6Exploit: No code on recordExposed services: Not assessed

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

The CVE record's CNA (VulnCheck) lists siyuan-note siyuan versions before 3.7.2 as affected, and siyuan-note siyuan versions 3.7.2 as unaffected. No release containing a fix is confirmed on record.

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.

CVSS v3
9.6
EG Score
9.6CRITICALmedium 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)
Severity96% × 45%
Impact severity (EG Severity): CVSS 9.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
47th
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 (9.6): severity, escalated by confirmed exploitation. This CVE's 9.6 is its impact severity (EG Severity), not escalated.

EG Severity
9.6 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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, Track* at medium and Attend at high mission impact.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

July 27, 2026

Last Modified

October 24, 2026

Advisory Details (2)

Auto-updated Oct 7, 2026
No fix on record yet. Sources: github.
GitHub advisoryMentions a patch (unverified)

Reflected XSS to OS RCE in the SiYuan desktop via `siyuan://` deep link · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6gx2-8gcr-x83f
Web page

SiYuan Desktop before v3.7.2 Reflected XSS to RCE via siyuan Protocol | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-desktop-before-reflected-xss-to-rce-via-siyuan-protocol

Vendor Advisories for CVE-2026-66395(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 14× in last 7d / 60× 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 494 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 394 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-11-13 15:02 UTCEchelonGraph re-scored
  3. 2026-11-13 15:02 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  4. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-11-12 13:26 UTCEchelonGraph re-scored
  6. 2026-11-12 13:26 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  7. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  8. 2026-11-11 11:50 UTCEchelonGraph re-scored
  9. 2026-11-11 11:50 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  10. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  11. 2026-11-10 10:13 UTCEchelonGraph re-scored
  12. 2026-11-10 10:13 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  13. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  14. 2026-11-09 08:33 UTCEchelonGraph re-scored
  15. 2026-11-09 08:33 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  16. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  17. 2026-11-08 06:57 UTCEchelonGraph re-scored
  18. 2026-11-08 06:57 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  19. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  20. 2026-11-07 05:21 UTCEchelonGraph re-scored
  21. 2026-11-07 05:21 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  22. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  23. 2026-11-06 15:25 UTCOSV refresh
  24. 2026-11-06 03:45 UTCEchelonGraph re-scored
  25. 2026-11-06 03:45 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
Show 75 more
  1. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-11-05 02:10 UTCEchelonGraph re-scored
  3. 2026-11-05 02:10 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  4. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-11-04 00:33 UTCEchelonGraph re-scored
  6. 2026-11-04 00:33 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  7. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  8. 2026-11-02 22:58 UTCEchelonGraph re-scored
  9. 2026-11-02 22:58 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  10. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  11. 2026-11-01 21:21 UTCEchelonGraph re-scored
  12. 2026-11-01 21:21 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  13. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  14. 2026-10-31 19:45 UTCEchelonGraph re-scored
  15. 2026-10-31 19:45 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  16. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  17. 2026-10-30 18:10 UTCEchelonGraph re-scored
  18. 2026-10-30 18:10 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  19. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-10-29 16:34 UTCEchelonGraph re-scored
  21. 2026-10-29 16:34 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  22. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  23. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-10-28 14:58 UTCEchelonGraph re-scored
  25. 2026-10-28 14:58 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  26. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-10-27 13:06 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  28. 2026-10-26 16:53 UTCEchelonGraph re-scored
  29. 2026-10-26 16:53 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  30. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  31. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  32. 2026-10-25 15:03 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  33. 2026-10-25 14:11 UTCEchelonGraph re-scored
  34. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  35. 2026-10-24 13:26 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  36. 2026-10-23 19:19 UTCEchelonGraph re-scored
  37. 2026-10-23 19:18 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  38. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  39. 2026-10-22 17:40 UTCEchelonGraph re-scored
  40. 2026-10-22 17:40 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  41. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  42. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-10-21 15:51 UTCEchelonGraph re-scored
  44. 2026-10-21 15:51 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  45. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  46. 2026-10-20 14:16 UTCEchelonGraph re-scored
  47. 2026-10-20 14:16 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  48. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  49. 2026-10-19 12:38 UTCEchelonGraph re-scored
  50. 2026-10-19 12:38 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  51. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  52. 2026-10-18 11:01 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  53. 2026-10-18 03:21 UTCEchelonGraph re-scored
  54. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  55. 2026-10-17 09:24 UTCEchelonGraph re-scored
  56. 2026-10-17 09:24 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  57. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  58. 2026-10-16 07:49 UTCEchelonGraph re-scored
  59. 2026-10-16 07:49 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  60. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  61. 2026-10-15 06:12 UTCEchelonGraph re-scored
  62. 2026-10-15 06:12 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  63. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  64. 2026-10-14 01:48 UTCEchelonGraph re-scored
  65. 2026-10-14 01:48 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  66. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  67. 2026-10-12 22:01 UTCEchelonGraph re-scored
  68. 2026-10-12 22:00 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  69. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  70. 2026-10-12 15:46 UTCEchelonGraph re-scored
  71. 2026-10-12 06:02 UTCGHSA enrichmentGHSA-x52j-m89g-wh64 · GitHub severity CRITICAL · GitHub CVSS 9.6
  72. 2026-10-11 19:31 UTCEchelonGraph re-scored
  73. 2026-10-11 16:46 UTCEchelonGraph re-scored
  74. 2026-10-11 14:07 UTCEchelonGraph re-scored
  75. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile

Frequently asked(5)

What is CVE-2026-66395?
CVE-2026-66395 is a critical-severity vulnerability; its CVE record was published on July 27, 2026. SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with…
When was CVE-2026-66395 made public?
CVE-2026-66395 was made public on July 13, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on July 27, 2026. EchelonGraph's copy of the record carries a last-modified date of October 24, 2026; the record at its source may have been updated since.
Is CVE-2026-66395 actively exploited?
CVE-2026-66395 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66395?
CVE-2026-66395 has a CVSS base score of 9.6 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66395?
No fix for CVE-2026-66395 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (VulnCheck) lists siyuan-note siyuan versions before 3.7.2 as affected, and siyuan-note siyuan versions 3.7.2 as unaffected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-66395 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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