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SiYuan: Non-administrator responses from /api/system/getConf omit three secrets that the configuration-export path explicitly strips, disclosing the session-cookie signing key and the OS username to anonymous readers

High severity GitHub Reviewed Published Jul 25, 2026 in siyuan-note/siyuan • Updated Sep 4, 2026

Package

gomod github.com/siyuan-note/siyuan/kernel (Go)

Affected versions

< 0.0.0-20260725132049-2d8b98395a91

Patched versions

0.0.0-20260725132049-2d8b98395a91

Description

CVE: This vulnerability corresponds to CVE-2026-72793.

Summary

/api/system/getConf is registered with CheckAuth only and is reachable by the publish RoleReader token, and anonymously when Publish.Auth.Enable is false. Its non-administrator masking chain is a blocklist that enumerates fields individually. Three fields that the configuration-export endpoint in the same file deliberately clears are absent from that blocklist and are returned to readers:

Field JSON What it is Cleared by exportConf at
Conf.CookieKey cookieKey The session-cookie signing key kernel/api/system.go:360
Conf.Export.PandocBin export.pandocBin Absolute path embedding the OS username kernel/api/system.go:338
Conf.NotebookCrypto notebookCrypto Encrypted-notebook key material kernel/api/system.go:360

The project has already classified all three as values that must not leave the server. The reader-facing path returns them.

Details

Route. kernel/api/router.go:70 : POST /api/system/getConfmodel.CheckAuthgetConf. No CheckReadonly, no CheckAdminRole.

The masking chain, and what each stage covers. getConf masks through GetMaskedConf()HideConfSecret() (non-administrators) → FilterConfByPublishIgnore() (readers) → a browser-request path strip.

  • GetMaskedConf: UserData, MCPOAuth, AccessAuthCode.
  • HideConfSecret: AI, Api, Flashcard, ServerAddrs, Publish, Repo, Sync, Secrets, Variables, and the System paths. No reference to CookieKey or Export.PandocBin.
  • FilterConfByPublishIgnore: UILayout only.
  • Browser strip (kernel/api/system.go:630-631): System paths only.

Each stage names fields explicitly, so any field nobody thought to add is returned by default.


1. CookieKey: the live session-signing key.

The value is passed straight into the session store at startup:

cli/cmd/serve.go:67          go server.Serve(false, model.Conf.CookieKey)
kernel/server/serve.go:152   sessionStore = cookie.NewStore([]byte(cookieKey))
kernel/server/serve.go:159   ginServer.Use(sessions.Sessions("siyuan", sessionStore))

gin-contrib/sessions/cookie.NewStore constructed with a single key uses that key as the gorilla/securecookie HMAC key. The siyuan session cookie is signed with the value this endpoint hands out, so an attacker holding it can mint and modify session cookies the server accepts as authentic.

Escalating a forged session to administrator additionally requires the forged SessionData to carry the matching AccessAuthCode which is masked or the instance to have no access-auth code configured, which is a common deployment. The unconditional impact, present on every instance, is disclosure of a persistent cryptographic secret to an unauthenticated party. Rotating it invalidates every active session, so it cannot be quietly refreshed.


2. Export.PandocBin: bypasses a shipped privacy control.

The field is an absolute path that embeds the OS username by construction:

conf/export.go:35        PandocBin string `json:"pandocBin"`
model/conf.go:430-431    if "" == Conf.Export.PandocBin { Conf.Export.PandocBin = util.PandocBinPath }
util/pandoc.go:154       PandocBinPath = filepath.Join(tempPandocDir, "bin", "pandoc.exe")
util/pandoc.go:134       tempPandocDir = filepath.Join(TempDir, "pandoc")
util/working.go:359      TempDir = filepath.Join(WorkspaceDir, "temp")
util/working.go:312      defaultWorkspaceDir = filepath.Join(userProfile, "SiYuan")

C:\Users\<username>\SiYuan\temp\pandoc\bin\pandoc.exe

This one is notable beyond the disclosure itself, because a control was shipped specifically to prevent it. kernel/api/system.go:630 adds, for browser requests:

if util.IsBrowserRequest(c) {
    maskedConf.System.WorkspaceDir = ""
    maskedConf.System.AppDir = ""
    maskedConf.System.ConfDir = ""
    maskedConf.System.DataDir = ""
    maskedConf.System.HomeDir = ""
}   // 避免泄露用户名等敏感信息

The comment states the goal plainly: avoid leaking the username and other sensitive information. The block enumerates only System.* and misses Export.PandocBin, which carries the same username through the same response. A publish reader is a browser request, so the System paths are blanked while export.pandocBin passes through intact. Where an administrator has configured a custom pandoc location, that path is disclosed instead still a filesystem-layout disclosure.


3. NotebookCrypto. Encrypted-notebook key material is likewise absent from HideConfSecret while exportConf sets it to nil. Reported previously and included here only because it is the third instance of the same root cause; the fix below closes all three together.


The root cause is the blocklist itself. exportConf (kernel/api/system.go:299) clones the configuration and clears each secret before returning it CookieKey, NotebookCrypto, Export.PandocBin, Account, Stat, System.ID, the AI keys. That cloner is the project's own working inventory of what must not leave the server. getConf's non-administrator path maintains a separate, shorter list that has now diverged from it in three places. Any future secret added to the config will default to exposed on the reader path unless someone remembers to extend the blocklist.

Proof of Concept

Precondition: publish mode enabled (default port 6808); anonymous when Publish.Auth.Enable is false, otherwise any publish reader account.

POST http://127.0.0.1:6808/api/system/getConf
{}

→ 200. The conf object contains:
     cookieKey          — the session-signing key, cleartext
     export.pandocBin   — absolute path containing the OS username
     notebookCrypto     — encrypted-notebook key material

Differential check against the endpoint that strips them, same instance:

POST http://127.0.0.1:6808/api/system/exportConf

→ cookieKey is empty, export.pandocBin is empty, notebookCrypto is null

The same three values are withheld by one endpoint and returned by the other.

Impact

An anonymous reader in publish mode or any publish RoleReader obtains the server's session-cookie signing key, permitting forgery and tampering of session cookies the server validates as authentic, with administrator authentication reachable on instances that have no access-auth code configured. The same response discloses the operating-system username and workspace layout, defeating a control added specifically to prevent that disclosure, and encrypted-notebook key material.

Suggested fix

Route non-administrator getConf responses through the exportConf cloner rather than extending HideConfSecret field by field. The cloner already handles every field named here and is the list the project actually maintains; keeping two divergent inventories of the same secrets is what produced all three gaps. If a targeted patch is preferred in the interim, clear CookieKey and NotebookCrypto in HideConfSecret and add Export.PandocBin to the IsBrowserRequest block, then audit the config struct for any remaining absolute-path or secret-bearing field.

References

@88250 88250 published to siyuan-note/siyuan Jul 25, 2026
Published to the GitHub Advisory Database Sep 4, 2026
Reviewed Sep 4, 2026
Last updated Sep 4, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(15th percentile)

Weaknesses

Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. Learn more on MITRE.

CVE ID

CVE-2026-72793

GHSA ID

GHSA-h4v5-crx2-3cv4

Source code

Credits

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