CVE-2026-59809

MEDIUMPre-NVD 4.94.9—
EchelonGraph scoreHIGH confidence

Score 4.9 from GitHub Security Advisory published 2026-08-22. a secondary CVSS source baseline 4.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
4.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.9Exploit: None knownExposed: 0

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

SiYuan before v3.8.0 interpolates secret placeholders into the destination URL parameter of the http_request MCP tool, allowing attackers to exfiltrate stored secrets. An MCP client can craft a request with an attacker-controlled URL containing secret placeholders to send plaintext secret values to any public host without confirmation.

CVSS v3
4.9
EG Score
4.9(high)
EG Risk
22(Track)
EG Risk 22/100SSVC: 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
Severity49% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

August 22, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Aug 22, 2026
Patch available. Sources: github.
generic

SiYuan before v3.8.0 Secret Exfiltration via http_request URL | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url
github Patch Available

Secret placeholders in the http_request MCP tool are interpolated into the destination URL, enabling exfiltration of stored secrets to any attacker-chosen host · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx

Vendor Advisories for CVE-2026-59809(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 21× in last 7d / 24× 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. 2026-08-30 02:27 UTCEG score recompute
  2. 2026-08-30 02:27 UTCGHSA enrichment
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-29 01:01 UTCEG score recompute
  5. 2026-08-29 01:01 UTCGHSA enrichment
  6. 2026-08-28 21:42 UTCEPSS rescore
  7. 2026-08-27 18:55 UTCEG score recompute
  8. 2026-08-27 18:55 UTCGHSA enrichment
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-26 17:25 UTCEG score recompute
  11. 2026-08-26 17:25 UTCGHSA enrichment
  12. 2026-08-26 16:23 UTCEG score recompute
  13. 2026-08-26 16:23 UTCGHSA enrichment
  14. 2026-08-26 14:46 UTCEPSS rescore
  15. 2026-08-25 18:22 UTCEG score recompute
  16. 2026-08-25 18:22 UTCGHSA enrichment
  17. 2026-08-25 13:49 UTCEPSS rescore
  18. 2026-08-24 16:55 UTCEG score recompute
  19. 2026-08-24 16:55 UTCGHSA enrichment
  20. 2026-08-23 14:48 UTCEG score recompute
  21. 2026-08-23 14:48 UTCGHSA enrichment
  22. 2026-08-22 13:21 UTCEG score recompute
  23. 2026-08-22 12:46 UTCEG score recompute
  24. 2026-08-22 12:45 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-59809?
CVE-2026-59809 is a medium vulnerability published on August 22, 2026. SiYuan before v3.8.0 interpolates secret placeholders into the destination URL parameter of the http_request MCP tool, allowing attackers to exfiltrate stored secrets. An MCP client can craft a request with an attacker-controlled URL containing secret placeholders to send plaintext secret values to…
When was CVE-2026-59809 disclosed?
CVE-2026-59809 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59809 actively exploited?
CVE-2026-59809 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 84.6% of all scored CVEs.
What is the CVSS score of CVE-2026-59809?
CVE-2026-59809 has a CVSS v3 base score of 4.9 (NVD).
How do I remediate CVE-2026-59809?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59809, 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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