SiYuan before v3.8.1 SSRF via DNS-Rebinding TOCTOU
Summary
| CVE | CVE-2026-82234 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-28 12:16:33 UTC |
| Updated | 2026-08-28 12:16:33 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 8.4 HIGH from [email protected]
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-918 | CWE-918 Server-Side Request Forgery (SSRF)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 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/E:X/C... |
| 4.0 | CNA | CVSS | 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 |
| 3.1 | [email protected] | Primary | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N |
| 3.1 | CNA | CVSS | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
PassiveConfidentiality
HighIntegrity
LowAvailability
NoneSub Conf.
HighSub Integrity
LowSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
ChangedConfidentiality
HighIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Siyuan-note | Siyuan | affected 3.8.1 semver | Not specified |
| CNA | Siyuan-note | Siyuan | unaffected 3.8.1 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.vulncheck.com/advisories/siyuan-before-3.8.1-ssrf-via-dns-rebinding-toctou | [email protected] | www.vulncheck.com | |
| github.com/siyuan-note/siyuan/security/advisories/GHSA-x8gv-g2g3-65fj | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: joysinleung (en)
There are currently no legacy QID mappings associated with this CVE.