CVE-2026-66394

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

Score 8.7 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-27. a secondary CVSS source baseline 8.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: Elevated riskExposed: 0

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

SiYuan before v3.7.3 contains stored and reflected cross-site scripting vulnerabilities in SVG sanitization that allows authenticated attackers to execute scripts by bypassing the HTML parser-based cleaner. Attackers can hide script tags within desc, style, or noscript elements which the HTML parser treats as raw text but browsers interpret as executable SVG content when served as image/svg+xml, enabling script execution in the application origin.

CVSS v3
8.7
EG Score
8.7(medium)
EG Risk
55(Track)
EG Risk 55/100SSVC: 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
Severity87% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

July 27, 2026

Last Modified

July 28, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
Patch available. Sources: github.
generic

SiYuan before v3.7.3 Stored and Reflected XSS via SVG Sanitizer Bypass | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-stored-and-reflected-xss-via-svg-sanitizer-bypass
github Patch Available

Stored and reflected XSS in SiYuan through an SVG sanitizer bypass · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-99rq-75j6-5j9f

Vendor Advisories for CVE-2026-66394(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/siyuan-note/siyuan/kernel—0.0.0-20260714095344-f08dee71ba8e—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 21× in last 7d / 89× 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.

Showing the most recent 100 of 183 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66394?
CVE-2026-66394 is a high vulnerability published on July 27, 2026. SiYuan before v3.7.3 contains stored and reflected cross-site scripting vulnerabilities in SVG sanitization that allows authenticated attackers to execute scripts by bypassing the HTML parser-based cleaner. Attackers can hide script tags within desc, style, or noscript elements which the HTML…
When was CVE-2026-66394 disclosed?
CVE-2026-66394 was first published in the National Vulnerability Database on July 27, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66394 actively exploited?
CVE-2026-66394 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 80.9% of all scored CVEs.
What is the CVSS score of CVE-2026-66394?
CVE-2026-66394 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-66394?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66394, 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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