GHSA-34FJ-MWM6-FJFG
Vulnerability from github – Published: 2026-09-04 21:12 – Updated: 2026-09-04 21:12CVE: This vulnerability corresponds to CVE-2026-72794.
Summary
/api/system/getConf returns Conf.CookieKey, the key used to sign the server's session cookies in its response body. The endpoint is registered with CheckAuth only, so the field reaches the publish RoleReader token and the anonymous account when Publish.Auth.Enable is false.
The configuration-export endpoint in the same file strips this exact field before returning config, so the project already treats it as secret. The reader-facing masking path does not.
Details
| Item | Detail |
|---|---|
| Route | kernel/api/router.go:70 POST /api/system/getConf → model.CheckAuth → getConf |
| Middleware | CheckAuth only — no CheckReadonly, no CheckAdminRole |
| Leaked field | AppConf.CookieKey, serialized as cookieKey |
| Purpose of the field | Signing key for the siyuan session cookie |
The field survives every stage of the masking chain. getConf masks through GetMaskedConf() → HideConfSecret() (non-administrators) → FilterConfByPublishIgnore() (readers) → the browser-side System-path strip. CookieKey is removed by none of them:
GetMaskedConfmasksUserData,MCPOAuthandAccessAuthCodeonly.HideConfSecretnullsAI,Api,Flashcard,ServerAddrs,Publish,Repo,Sync,Secrets,Variablesand the System paths. It contains no reference toCookieKey.FilterConfByPublishIgnoretouchesUILayoutonly.- The browser-side strip removes System paths only.
The key is live, not vestigial. It 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 therefore signed with the value the endpoint hands out. An attacker holding it can mint and modify session cookies that the server accepts as authentic.
Guarded sibling, in the same file. exportConf (kernel/api/system.go:299) clones the configuration before returning it and explicitly clears both secrets:
kernel/api/system.go:360 clonedConf.CookieKey = ""
clonedConf.NotebookCrypto = nil
The project has already classified CookieKey as a value that must not leave the server. The getConf masking path omits the same field.
Ceiling is environment-dependent, floor is not. Escalating a forged session to administrator additionally requires the forged SessionData to carry the matching AccessAuthCode, which GetMaskedConf does mask or the instance to have no access-auth code configured, which is a common deployment. The unconditional impact, present on every instance, is the disclosure of a persistent cryptographic secret to an unauthenticated party together with the cookie-forgery capability that follows from it. Rotating the key invalidates all existing sessions, so this is not a secret that can be quietly refreshed.
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 response body's conf object contains a cookieKey field holding the
server's session-signing key in cleartext.
Differential check against the endpoint that does strip it:
POST http://127.0.0.1:6808/api/system/exportConf
→ cookieKey is empty, notebookCrypto is null
The same value is 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. This is a persistent cryptographic secret whose disclosure cannot be remediated without invalidating every active session. Possession of the key permits forging and tampering with siyuan session cookies that the server will validate as authentic. On instances with no access-auth code configured, or where a forged session's contents otherwise satisfy the server's checks, this extends to authenticating as a privileged user.
Suggested fix
Clear CookieKey in HideConfSecret for all non-administrator responses. The more durable fix is to route non-administrator getConf through the exportConf cloner, which already handles CookieKey, NotebookCrypto, Account, Stat, System.ID, Export.PandocBin and the AI keys replacing the current blocklist, which fails open on every field nobody thought to add, with the allowlist-style cloner the project already maintains.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/siyuan-note/siyuan/kernel"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.0.0-20260725123945-77421530be4a"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-72794"
],
"database_specific": {
"cwe_ids": [
"CWE-522"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-04T21:12:26Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "**CVE:** This vulnerability corresponds to [CVE-2026-72794](https://nvd.nist.gov/vuln/detail/CVE-2026-72794).\n\n### Summary\n\n`/api/system/getConf` returns `Conf.CookieKey`, the key used to sign the server\u0027s session cookies in its response body. The endpoint is registered with `CheckAuth` only, so the field reaches the publish `RoleReader` token and the anonymous account when `Publish.Auth.Enable` is `false`.\n\nThe configuration-export endpoint in the same file strips this exact field before returning config, so the project already treats it as secret. The reader-facing masking path does not.\n\n### Details\n\n| Item | Detail |\n|---|---|\n| Route | `kernel/api/router.go:70` `POST /api/system/getConf` \u2192 `model.CheckAuth` \u2192 `getConf` |\n| Middleware | `CheckAuth` only \u2014 no `CheckReadonly`, no `CheckAdminRole` |\n| Leaked field | `AppConf.CookieKey`, serialized as `cookieKey` |\n| Purpose of the field | Signing key for the `siyuan` session cookie |\n\n**The field survives every stage of the masking chain.** `getConf` masks through `GetMaskedConf()` \u2192 `HideConfSecret()` (non-administrators) \u2192 `FilterConfByPublishIgnore()` (readers) \u2192 the browser-side System-path strip. `CookieKey` is removed by none of them:\n\n- `GetMaskedConf` masks `UserData`, `MCPOAuth` and `AccessAuthCode` only.\n- `HideConfSecret` nulls `AI`, `Api`, `Flashcard`, `ServerAddrs`, `Publish`, `Repo`, `Sync`, `Secrets`, `Variables` and the System paths. It contains no reference to `CookieKey`.\n- `FilterConfByPublishIgnore` touches `UILayout` only.\n- The browser-side strip removes System paths only.\n\n**The key is live, not vestigial.** It is passed straight into the session store at startup:\n\n```\ncli/cmd/serve.go:67 go server.Serve(false, model.Conf.CookieKey)\nkernel/server/serve.go:152 sessionStore = cookie.NewStore([]byte(cookieKey))\nkernel/server/serve.go:159 ginServer.Use(sessions.Sessions(\"siyuan\", sessionStore))\n```\n\n`gin-contrib/sessions/cookie.NewStore` constructed with a single key uses that key as the `gorilla/securecookie` HMAC key. The `siyuan` session cookie is therefore signed with the value the endpoint hands out. An attacker holding it can mint and modify session cookies that the server accepts as authentic.\n\n**Guarded sibling, in the same file.** `exportConf` (`kernel/api/system.go:299`) clones the configuration before returning it and explicitly clears both secrets:\n\n```\nkernel/api/system.go:360 clonedConf.CookieKey = \"\"\n clonedConf.NotebookCrypto = nil\n```\n\nThe project has already classified `CookieKey` as a value that must not leave the server. The `getConf` masking path omits the same field.\n\n**Ceiling is environment-dependent, floor is not.** Escalating a forged session to administrator additionally requires the forged `SessionData` to carry the matching `AccessAuthCode`, which `GetMaskedConf` does mask or the instance to have no access-auth code configured, which is a common deployment. The unconditional impact, present on every instance, is the disclosure of a persistent cryptographic secret to an unauthenticated party together with the cookie-forgery capability that follows from it. Rotating the key invalidates all existing sessions, so this is not a secret that can be quietly refreshed.\n\n### Proof of Concept\n\nPrecondition: publish mode enabled (default port 6808); anonymous when `Publish.Auth.Enable` is `false`, otherwise any publish reader account.\n\n```\nPOST http://127.0.0.1:6808/api/system/getConf\n{}\n\n\u2192 200\n The response body\u0027s conf object contains a cookieKey field holding the\n server\u0027s session-signing key in cleartext.\n```\n\nDifferential check against the endpoint that does strip it:\n\n```\nPOST http://127.0.0.1:6808/api/system/exportConf\n\u2192 cookieKey is empty, notebookCrypto is null\n```\n\nThe same value is withheld by one endpoint and returned by the other.\n\n### Impact\n\nAn anonymous reader in publish mode or any publish `RoleReader` obtains the server\u0027s session-cookie signing key. This is a persistent cryptographic secret whose disclosure cannot be remediated without invalidating every active session. Possession of the key permits forging and tampering with `siyuan` session cookies that the server will validate as authentic. On instances with no access-auth code configured, or where a forged session\u0027s contents otherwise satisfy the server\u0027s checks, this extends to authenticating as a privileged user.\n\n### Suggested fix\n\nClear `CookieKey` in `HideConfSecret` for all non-administrator responses. The more durable fix is to route non-administrator `getConf` through the `exportConf` cloner, which already handles `CookieKey`, `NotebookCrypto`, `Account`, `Stat`, `System.ID`, `Export.PandocBin` and the AI keys replacing the current blocklist, which fails open on every field nobody thought to add, with the allowlist-style cloner the project already maintains.",
"id": "GHSA-34fj-mwm6-fjfg",
"modified": "2026-09-04T21:12:26Z",
"published": "2026-09-04T21:12:26Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-34fj-mwm6-fjfg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72794"
},
{
"type": "WEB",
"url": "https://github.com/siyuan-note/siyuan/commit/77421530be4ab1f43310d0f50fbab05d16c38675"
},
{
"type": "PACKAGE",
"url": "https://github.com/siyuan-note/siyuan"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/siyuan-before-session-cookie-key-disclosure-via-getconf"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "SiYuan: The session-cookie signing key (Conf.CookieKey) is returned to anonymous readers by /api/system/getConf"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.