CVE-2026-87811

HIGHPre-NVD 7.37.3—
EchelonGraph scoreHIGH confidence

Score 7.3 from GitHub Security Advisory (severity: HIGH) published 2026-09-09. a secondary CVSS source baseline 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.3Exploit: Elevated riskExposed: 0

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

SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling same-origin API requests and application state manipulation.

CVSS v3
7.3
EG Score
7.3(high)
EG Risk
49(Track*)
EG Risk 49/100SSVC: 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
Severity73% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

September 9, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Sep 9, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

SiYuan before v3.8.2 Stored XSS via notebook template paths | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-3.8.2-stored-xss-via-notebook-template-paths
github Patch Available🟡 PoC Available

Stored XSS in notebook configuration via unescaped template paths · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-v6wf-r2gr-rrgf

Vendor Advisories for CVE-2026-87811(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 28× in last 7d / 65× 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.

  1. 2026-09-25 05:20 UTCGHSA enrichment
  2. 2026-09-24 18:18 UTCEG score recompute
  3. 2026-09-24 18:18 UTCGHSA enrichment
  4. 2026-09-24 14:04 UTCEPSS rescore
  5. 2026-09-24 06:44 UTCGHSA enrichment
  6. 2026-09-23 19:43 UTCEG score recompute
  7. 2026-09-23 19:43 UTCGHSA enrichment
  8. 2026-09-23 17:54 UTCEPSS rescore
  9. 2026-09-23 08:42 UTCGHSA enrichment
  10. 2026-09-22 21:41 UTCEG score recompute
  11. 2026-09-22 21:41 UTCGHSA enrichment
  12. 2026-09-22 16:01 UTCEPSS rescore
  13. 2026-09-22 10:40 UTCGHSA enrichment
  14. 2026-09-21 23:31 UTCEG score recompute
  15. 2026-09-21 23:31 UTCGHSA enrichment
  16. 2026-09-21 21:09 UTCEPSS rescore
  17. 2026-09-21 12:29 UTCGHSA enrichment
  18. 2026-09-21 01:28 UTCEG score recompute
  19. 2026-09-21 01:28 UTCGHSA enrichment
  20. 2026-09-20 20:16 UTCEPSS rescore
  21. 2026-09-20 14:26 UTCGHSA enrichment
  22. 2026-09-20 03:21 UTCGHSA enrichment
  23. 2026-09-19 16:20 UTCEG score recompute
  24. 2026-09-19 16:20 UTCGHSA enrichment
  25. 2026-09-19 05:18 UTCEG score recompute
Show 40 more
  1. 2026-09-19 05:18 UTCGHSA enrichment
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 18:17 UTCGHSA enrichment
  4. 2026-09-18 07:15 UTCGHSA enrichment
  5. 2026-09-17 20:14 UTCEG score recompute
  6. 2026-09-17 20:14 UTCGHSA enrichment
  7. 2026-09-17 19:32 UTCEPSS rescore
  8. 2026-09-17 07:00 UTCGHSA enrichment
  9. 2026-09-16 19:59 UTCEG score recompute
  10. 2026-09-16 19:59 UTCGHSA enrichment
  11. 2026-09-16 14:09 UTCEPSS rescore
  12. 2026-09-16 08:54 UTCEG score recompute
  13. 2026-09-16 08:54 UTCGHSA enrichment
  14. 2026-09-16 05:15 UTCEPSS rescore
  15. 2026-09-15 20:50 UTCGHSA enrichment
  16. 2026-09-15 09:33 UTCEG score recompute
  17. 2026-09-15 09:33 UTCGHSA enrichment
  18. 2026-09-15 03:12 UTCEPSS rescore
  19. 2026-09-14 22:32 UTCGHSA enrichment
  20. 2026-09-14 11:31 UTCGHSA enrichment
  21. 2026-09-14 00:30 UTCEG score recompute
  22. 2026-09-14 00:30 UTCGHSA enrichment
  23. 2026-09-13 13:29 UTCGHSA enrichment
  24. 2026-09-13 02:27 UTCGHSA enrichment
  25. 2026-09-12 15:27 UTCEG score recompute
  26. 2026-09-12 15:26 UTCGHSA enrichment
  27. 2026-09-12 04:24 UTCGHSA enrichment
  28. 2026-09-11 17:23 UTCEG score recompute
  29. 2026-09-11 17:23 UTCGHSA enrichment
  30. 2026-09-11 14:53 UTCEPSS rescore
  31. 2026-09-11 14:53 UTCEPSS rescore
  32. 2026-09-11 05:53 UTCGHSA enrichment
  33. 2026-09-10 18:51 UTCGHSA enrichment
  34. 2026-09-10 07:48 UTCGHSA enrichment
  35. 2026-09-09 20:45 UTCGHSA enrichment
  36. 2026-09-09 13:33 UTCEG score recompute
  37. 2026-09-09 13:32 UTCGHSA enrichment
  38. 2026-09-09 12:25 UTCEG score recompute
  39. 2026-09-09 11:30 UTCEG score recompute
  40. 2026-09-09 11:29 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-87811?
CVE-2026-87811 is a high vulnerability published on September 9, 2026. SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling…
When was CVE-2026-87811 disclosed?
CVE-2026-87811 was first published in the National Vulnerability Database on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-87811 actively exploited?
CVE-2026-87811 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 72.3% of all scored CVEs.
What is the CVSS score of CVE-2026-87811?
CVE-2026-87811 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2026-87811?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-87811, 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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