CVE-2026-82234
SiYuan before v3.8.1 SSRF via DNS-Rebinding TOCTOU
- State
- Published
- Severity
- 8.4 High
- Published
- Aug 28, 2026
- Updated
- Aug 28, 2026
- Reserved
- Aug 28, 2026
Description
SiYuan versions before v3.8.1 contain a server-side request forgery vulnerability in the http_request and web_fetch agent tools that perform DNS resolution only at guard time without validating the connect-time resolution. Attackers can use DNS rebinding to answer the guard resolution with a public IP and the connect resolution with a private or metadata IP, bypassing the SSRF defense to access cloud instance metadata and internal services.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.4 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N | VulnCheck |
| 3.1 | 8.2 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N | VulnCheck |
Weaknesses
- CWE-918 Server-Side Request Forgery (SSRF)
Affected Products
| Product | Versions |
|---|---|
siyuansiyuan-note |
|
References
- GitHub Security Advisory (GHSA-x8gv-g2g3-65fj)vendor-advisory
- VulnCheck Advisory: SiYuan before v3.8.1 SSRF via DNS-Rebinding TOCTOUthird-party-advisory
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