SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

EPSS

• CVE-2026-82234: 0.36% estimated exploitation activity in the next 30 days; percentile 30.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Security Advisory — SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF) | Field | Value | |---|---| | Disclosed by | joysinleung (joysinleung@gmail.com) | | Report date | 2026-08-13 | | Product | SiYuan (思源笔记) — siyuan-note/siyuan | | Go module | github.com/siyuan-note/siyuan/kernel | | Affected versions | <= 3.8.0 (latest release at report time; dynamically verified on v3.8.0) | | Patched versions | 3.8.1 | | Component | kernel/util/httprequest.go (CheckHostSSRF), kernel/mcp/tools/httprequest.go, kernel/util/webfetch.go, kernel/util/net.go (SSRFSafeDialer) | | Relationship to prior advisory | Incomplete-fix variant of GHSA-rg26-cg95-gq6p (SSRF main-vector remediation). See §Relationship. | | EPSS (exploitation probability) | Low–Moderate. Requires the attacker to influence an AI Agent / MCP client into fetching an attacker-controlled domain (prompt-injection scenario documented by the tool itself). | | KEV (CISA Known Exploited) | No (not listed in CISA KEV at…

Published by the source

2 Oct 2026, 23:17 UTC

Last modified by the source

7 Oct 2026, 17:55 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-x8gv-g2g3-65fj

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6657

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-x8gv-g2g3-65fj

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# Patch Next advisory brief: CVE-2026-82234

Advisory: SiYuan Agent Tools SSRF via DNS-Rebinding TOCTOU (Bypass of CheckHostSSRF)
IDs: CVE-2026-82234, GHSA-x8gv-g2g3-65fj
Record: https://patchnext.com/advisories/cve-2026-82234 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/siyuan-note/siyuan/kernel 0.0.0-20260813142806-dd2778b70d02. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260813142806-dd2778b70d02; fixed in 0.0.0-20260813142806-dd2778b70d02

## Suggested inspection (read-only)
- Go github.com/siyuan-note/siyuan/kernel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/siyuan-note/siyuan/kernel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6657 (OSV record GO-2026-6657 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260813142806-dd2778b70d02 (fixed))
- Verified: https://osv.dev/vulnerability/GHSA-x8gv-g2g3-65fj (OSV record GHSA-x8gv-g2g3-65fj lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260813142806-dd2778b70d02 (fixed))
- Verified: https://github.com/advisories/GHSA-x8gv-g2g3-65fj (GitHub-reviewed advisory GHSA-x8gv-g2g3-65fj lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260813142806-dd2778b70d02)

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