SSRF in Siyuan-Note Siyuan
CVE-2026-82234
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (28.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-x8gv-g2g3-65fj (vendor-advisory)
- www.vulncheck.com/advisories/siyuan-before-3.8.1-ssrf-via-dns-rebinding-toctou (third-party-advisory)
Frequently asked questions
- What is CVE-2026-82234?
- CVE-2026-82234 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.2/10. Published 2026-08-28.
- How severe is CVE-2026-82234?
- High severity. CVSS v3 base score is 8.2 out of 10.