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CVE-2026-126393 SiYuan before 3.8.10 SSRF via Skill-Install Download Redirect and DNS Rebinding

5.3 mediumEPSS 0.2%

Medium (5.3) in siyuan-note siyuan. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.

On this page
SiYuan before 3.8.10 contains a server-side request forgery vulnerability in the skill-install download path because fetchBytes performs only a parse-time hostname check instead of using ssrfSafeClient. Attackers can supply a skill URL via the MCP skill install action that redirects or DNS-rebinds to loopback addresses, reaching internal services and metadata endpoints.

Severity

CVSS 4.0

5.3 medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

CVSS 3.1

6.1 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.2% estimated probability of exploitation activity in the next 30 days; 16th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-918 Server-Side Request Forgery (SSRF)
OWASP Top 10
A01:2025 Broken Access Control
Published
Modified
Assigned by
VulnCheck (CNA)
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
siyuan-note siyuanbefore 3.8.10

Attack patterns (CAPEC)

  • CAPEC-664 Server Side Request Forgery Likelihood: High · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

History

  1. The NVD deferred its analysis

Changes since this site first stored the record. The same for every record: /api/public/changes.

References

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