# CVE-2026-72812: SiYuan missing authorization in refreshBacklink endpoint

Source: https://junglewise.ai/threats/cve-2026-72812-siyuan-missing-authorization-in-refreshbacklink-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-03. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-72812 · Severity: medium · CVSS 6.5 · Published 2026-09-03

SiYuan is a note-taking application with a publish feature that allows users to share documents. An unauthenticated user or low-privileged reader can call the `/api/ref/refreshBacklink` endpoint in publish mode to trigger persistent writes to the server's database, bypassing read-only protections and causing resource exhaustion. This allows attackers to perform denial-of-service attacks and violate the integrity of the application's invariants without needing credentials.

Technologies: [github.com/siyuan-note/siyuan/kernel (Go)](https://junglewise.ai/threats/technologies/github-com-siyuan-note-siyuan-kernel). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-72812 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72812 being exploited in the wild.

**How severe is CVE-2026-72812?** Medium severity, with a CVSS score of 6.5, published 3 September 2026.

**Which products and versions are affected?** github.com/siyuan-note/siyuan/kernel (Go) < 0.0.0-20260723002528-7d273c271ce1, SEMVER:introduced=0,fixed=0.0.0-20260723002528-7d273c271ce1.

**Is there a fix for CVE-2026-72812?** Yes. github.com/siyuan-note/siyuan/kernel (Go): upgrade to 0.0.0-20260723002528-7d273c271ce1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-72812 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-72812?** Check whether you run github.com/siyuan-note/siyuan/kernel (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/siyuan-note/siyuan/kernel (Go): upgrade to 0.0.0-20260723002528-7d273c271ce1 or later

  ```sh
  go get github.com/siyuan-note/siyuan/kernel@v0.0.0-20260723002528-7d273c271ce1
  ```


## Technical details

The `/api/ref/refreshBacklink` endpoint is a POST handler that lacks proper authorization guards. Unlike similar mutating endpoints that enforce `CheckAdminRole`, `CheckReadonly`, or inline `IsReadOnlyRoleContext` checks, this endpoint only requires `CheckAuth`, which admits reader-role users and anonymous accounts when publish mode authentication is disabled. When called, the handler invokes `model.RefreshBacklink(id)`, which executes a full write chain: flushing the transaction queue, performing global reference scans, loading and parsing trees from disk, and enqueuing database writes. The endpoint does not honor the global `util.ReadOnly` flag and accepts attacker-controlled block IDs without per-object publish-access validation, allowing readers to reindex documents outside their scope. This is reachable over the network with no authentication required in default publish configurations.

## Affected products

- SiYuan SiYuan before 0.0.0-20260723002528-7d273c271ce1

## Identifiers

- CVE-2026-72812
- GHSA-wgwx-479j-23vq
- GO-2026-6408

## Timeline

- 2026-07-23: disclosed: Initially published to GitHub Advisory Database
- 2026-09-03: advisory: Advisory updated with full details
- 2026-07-23: patched: Patched in commit 7d273c271ce1

## References

- [https://api.github.com/users/Shirshakhtml](https://api.github.com/users/Shirshakhtml)
- [https://github.com/Shirshakhtml](https://github.com/Shirshakhtml)
- [https://api.github.com/users/Shirshakhtml/gists%7B/gist_id%7D](https://api.github.com/users/Shirshakhtml/gists%7B/gist_id%7D)
- [https://api.github.com/users/Shirshakhtml/repos](https://api.github.com/users/Shirshakhtml/repos)
- [https://avatars.githubusercontent.com/u/75179984?v=4](https://avatars.githubusercontent.com/u/75179984?v=4)
- [https://api.github.com/users/Shirshakhtml/events%7B/privacy%7D](https://api.github.com/users/Shirshakhtml/events%7B/privacy%7D)

## Related threats

- [SiYuan publish filter information disclosure in local storage](https://junglewise.ai/threats/go-2026-6836-siyuan-the-publish-filter-for-local-storage-returns-the-7f022e62)
- [SiYuan WebSocket parser differential allows unauthenticated event stream access](https://junglewise.ai/threats/cve-2026-73054-siyuan-a-parser-differential-between-the-websocket-keepalive)
- [SiYuan authFilePublishAccess information disclosure](https://junglewise.ai/threats/cve-2026-73630-siyuan-authfilepublishaccess-distinguishes-hidden-and-forbidden)
- [SiYuan database backlink information disclosure via publish filter](https://junglewise.ai/threats/cve-2026-73049-siyuan-the-publish-filter-for-database-backlinks-consults-the)
- [SiYuan local storage endpoint discloses administrator activity](https://junglewise.ai/threats/siyuan-the-publish-filter-for-local-storage-returns-the-administrator-s-fab71d28)