siyuan before v3.7.4 Session Cookie Key Disclosure via getConf

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

siyuan versions before v3.7.4 expose the session cookie signing key through the /api/system/getConf endpoint to unauthenticated users in publish mode. Attackers can retrieve the CookieKey value and forge valid session cookies to impersonate users or gain administrative access.

Source published

12 Aug 2026 19:07:41 UTC

Source modified

14 Aug 2026 16:52:03 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CVSS 3.1 · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

siyuan versions before v3.7.4 expose the session cookie signing key through the /api/system/getConf endpoint to unauthenticated users in publish mode. Attackers can retrieve the CookieKey value and forge valid session cookies to impersonate users or gain administrative access.

Source published

12 Aug 2026 20:17:50 UTC

Source modified

24 Oct 2026 15:10:00 UTC

Observed here

25 Oct 2026 15:19:03 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

**CVE:** This vulnerability corresponds to [CVE-2026-72794](https://nvd.nist.gov/vuln/detail/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: - `GetMaskedConf` masks `UserData`, `MCPOAuth` and `AccessAuthCode` only. - `HideConfSecret` nulls `AI`, `Api`, `Flashcard`, `ServerAddrs`, `Publish`, `Repo`, `Sync`, `Secrets`, `Variables` and the System paths. It contains no reference to `CookieKey`. - `FilterConfByPublishIgnore` touches `UILayout` only. - 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.

Source published

4 Sep 2026 21:12:26 UTC

Source modified

10 Sep 2026 15:25:33 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Publisher rating · HIGH

SiYuan: The session-cookie signing key (Conf.CookieKey) is returned to anonymous readers by /api/system/getConf in github.com/siyuan-note/siyuan/kernel

Source published

10 Sep 2026 14:48:42 UTC

Source modified

10 Sep 2026 15:15:14 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.