SiYuan: Missing authorization on refreshBacklink allows anonymous readers to trigger persistent server-side writes and unauthenticated resource amplification (publish mode)

Exploitation

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

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS

• CVE-2026-72812: 0.38% estimated exploitation activity in the next 30 days; percentile 31.77 (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.

CVE: This vulnerability corresponds to CVE-2026-72812. Summary The /api/ref/refreshBacklink endpoint is gated by CheckAuth only. Unlike its mutating siblings, it carries no CheckAdminRole, no CheckReadonly, and no inline reader-role guard so it falls through all three authorization mechanisms the codebase uses to protect write operations. A publish RoleReader or the anonymous account when Publish.Auth.Enable is false can invoke it, forcing the server to flush its pending write-transaction queue, scan all references globally, load and parse referencing trees from disk, and enqueue database writes. This violates the read-only invariant (it writes even in a globally read-only workspace), provides an unauthenticated resource-amplification/DoS primitive, and applies no per-object access check to the caller-supplied ID. Details Route / auth tier. router.go: Handle("POST", "/api/ref/refreshBacklink", model.CheckAuth, refreshBacklink), CheckAuth only. CheckAuth admits RoleReader; the publish…

Published by the source

3 Sep 2026, 22:23 UTC

Last modified by the source

10 Sep 2026, 15:15 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wgwx-479j-23vq

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6408

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wgwx-479j-23vq

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# Patch Next advisory brief: CVE-2026-72812

Advisory: SiYuan: Missing authorization on refreshBacklink allows anonymous readers to trigger persistent server-side writes and unauthenticated resource amplification (publish mode)
IDs: CVE-2026-72812, GHSA-wgwx-479j-23vq
Record: https://patchnext.com/advisories/cve-2026-72812 (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: Medium (CVSS 6.5)
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 0.0.0-20260723002528-7d273c271ce1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260723002528-7d273c271ce1; fixed in 0.0.0-20260723002528-7d273c271ce1

## 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/GHSA-wgwx-479j-23vq (OSV record GHSA-wgwx-479j-23vq lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260723002528-7d273c271ce1 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6408 (OSV record GO-2026-6408 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260723002528-7d273c271ce1 (fixed))
- Verified: https://github.com/advisories/GHSA-wgwx-479j-23vq (GitHub-reviewed advisory GHSA-wgwx-479j-23vq lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260723002528-7d273c271ce1)

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