GHSA-36v8-mpjm-8j5r is a high-severity (CVSS 8.6) CWE-862 vulnerability in github.com/siyuan-note/siyuan/kernel. A fix is available for github.com/siyuan-note/siyuan/kernel — see the affected versions and patch details below.
SiYuan: Cross-boundary content disclosure via getBacklinkDoc/getBackmentionDoc (publish mode): reader-reachable rendered DOM of publish-forbidden docs; sibling list endpoints are filtered
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-36v8-mpjm-8j5r.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-36v8-mpjm-8j5r plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/siyuan-note/siyuan/kernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
CVE: This vulnerability corresponds to CVE-2026-68586.
Summary
The backlink API splits into list endpoints (which documents reference a block) and content endpoints (the rendered text of those referencing blocks). The list endpoints apply a publish-access filter, the content endpoints do not. As a result, /api/ref/getBacklinkDoc and /api/ref/getBackmentionDoc return the rendered DOM of blocks belonging to a publish-forbidden document to an anonymous reader, with no access check.
Both content endpoints are gated by CheckAuth only, reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false.
Details
The asymmetry between the list and content sides is the tell that this is an oversight, not intended behavior:
| Endpoint | Returns | Publish-access filter | Route |
|---|---|---|---|
getBacklink | list (*Path) | FilterPathsByPublishAccess - present | CheckAuth |
getBacklink2 | list (*Path) | FilterPathsByPublishAccess - present | CheckAuth |
getBacklinkDoc | rendered DOM | none | CheckAuth |
getBackmentionDoc | rendered DOM | none | CheckAuth |
model/backlink.go contains no publish-access reference anywhere, and Backlink.DOM is the rendered HTML of the referencing blocks. getBacklinkDoc(defID, refTreeID) returns the rendered content of blocks in refTreeID - including a publish-forbidden, publish-disabled, or password-protected document with no access check. The filtered list siblings (getBacklink/getBacklink2) demonstrate that the publish boundary is meant to apply to this data; the content endpoints simply omit it.
A reader is not limited to the filtered backlink list, they call getBacklinkDoc directly with any refTreeID. This also yields a reference-existence oracle: the response reveals whether the forbidden document refTreeID references the block defID.
Proof of Concept
Reproduced on a local instance (SiYuan running locally, publish mode enabled on port 6808, publish Basic Auth disabled). Setup: a publish-forbidden document D (REFTREEID) whose body contains the unique marker SECRET_MARKER_77 and which references a block DEFID in a separate known document.
1. Mark the target document publish-forbidden (admin action, the boundary that should block reads):
POST http://127.0.0.1:6806/api/filetree/setPublishAccess
Authorization: Token <admin-token>
{"id":"REFTREEID","visible":false,"password":"","disable":true}
2. Baseline: the list endpoint correctly hides the forbidden doc from the reader (anonymous, port 6808):
POST http://127.0.0.1:6808/api/ref/getBacklink2
{"id":"DEFID","k":"","mk":""}
The returned backlinks do not include the forbidden document D, the list side is filtered.
3. Disclosure: the content endpoint returns the forbidden doc's blocks anyway (anonymous, port 6808):
POST http://127.0.0.1:6808/api/ref/getBacklinkDoc
{"defID":"DEFID","refTreeID":"REFTREEID","keyword":""}
Returns HTTP 200; data.backlinks[].dom contains SECRET_MARKER_77, the rendered content of the publish-forbidden document, returned to an anonymous reader. getBackmentionDoc behaves identically for mention-type references.
Impact
An anonymous reader (publish mode with auth disabled) or any publish RoleReader, can read the rendered content of a publish-forbidden document's referencing blocks, defeating a boundary the administrator explicitly configured, and can determine whether a forbidden document references a given block (a reference-existence oracle).
Precondition (stated honestly): the request requires refTreeID (the forbidden document's ID) and defID (a block it references). defID may be any published/known block, so if the forbidden document references any public content, defID is known and only refTreeID need be supplied. Block/document IDs for forbidden documents are also obtainable from other CheckAuth-only endpoints that lack the publish-access filter (reported separately). This endpoint alone does not enumerate arbitrary documents; it discloses content once an ID is known.
Impact is confidentiality-only: content disclosure plus a reference-existence oracle, no modification. No admin role, CSRF token, or write permission is required. Encrypted notebooks are out of scope.
Suggested fix
Apply the same publish-access check the list siblings use. In getBacklinkDoc/getBackmentionDoc, filter each Backlink by its source document's box/path via CheckPathAccessableByPublishIgnore plus the publish-password cookie check consistent with FilterPathsByPublishAccess in getBacklink/getBacklink2. Any endpoint returning rendered block DOM should enforce the same publish boundary as the corresponding list endpoint.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/siyuan-note/siyuan/kernel | all versions | 0.0.0-20260721014413-f45749a7ef6ego get github.com/siyuan-note/siyuan/kernel@v0.0.0-20260721014413-f45749a7ef6e |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/siyuan-note/siyuan/kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/siyuan-note/siyuan/kernel to 0.0.0-20260721014413-f45749a7ef6e or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-36v8-mpjm-8j5r is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-36v8-mpjm-8j5r can be triaged on real exposure rather than presence alone.
Tailored to GHSA-36v8-mpjm-8j5r. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-36v8-mpjm-8j5r in your dependencies?
O3 Security finds GHSA-36v8-mpjm-8j5r across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.