VulnerabilityPublished 14 Aug 2026Updated 18 Aug 2026

CVE-2026-72810: siyuan · Missing Authorization

Affects siyuanSource CVE Database V5

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Not known to be exploited · CVSS 9.2 Critical : upgrade to 3.7.4 as a priority.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 4.0 base score

9.2Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.7.4

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 14 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade siyuan to 3.7.4.

Affected software

Product	Affected	Fixed in
siyuan-notesiyuan	Affected <3.7.4	Fixed in 3.7.4

AI-suggested

If you cannot patch yet, restrict access to the WebSocket broadcast interface and monitor for unauthorized connections if possible.

Description

**CVE:** This vulnerability corresponds to [CVE-2026-72810](https://nvd.nist.gov/vuln/detail/CVE-2026-72810). ### Summary WebSocket sessions established through the publish surface (port 6808, `RoleReader` anonymous when `Publish.Auth.Enable` is `false`) are added to the same broadcast session pool as authenticated sessions. The kernel's broadcast functions push content events transactions carrying block DOM, document save/create, move/rename to every session in the pool with no role or publish-access filtering. As a result, an anonymous reader who holds a WebSocket connection open passively receives a real-time feed of every edit made in the workspace, including edits to password-protected, publish-forbidden, and unpublished documents. Because these events are delivered over the push channel and never pass through an HTTP handler, none of the publish-access filters that gate the HTTP endpoints apply. ### Details **Session admission.** `HandleConnect` admits the injected `RoleReader` publish token, and the session is registered via `AddPushChan` into the same `sessions` pool used for authenticated clients. **Unfiltered broadcast.** The broadcast functions (`Broadcast`, `broadcastOthers`, `broadcastOtherAppMains`, …) write to every session in the pool with no role or publish-access check. The `isPublish` flag on a session is consulted only to send the "service closed" notice it is never used to gate content. Content events are pushed via `PushModeBroadcast → Broadcast()`, so transactions (with rendered block DOM), `savedoc`/create, and `moveDoc`/rename events reach the publish reader's socket unfiltered. **No HTTP filter applies.** This is a push channel, the events originate from the kernel's own edit pipeline and are broadcast directly to open sockets. They never traverse an HTTP handler, so the publish-access filters that gate the HTTP content endpoints (and the incomplete/missing filters reported separately on those endpoints) are not in the path at all. The WebSocket route (`/ws`) is `CheckAuth`-only, which the publish `RoleReader` token satisfies. ### Proof of Concept Reproduced on a local instance (SiYuan running locally, publish mode enabled on port 6808, publish Basic Auth disabled). An anonymous client (no token, no password) opens `wss://127.0.0.1:6808/ws` and holds it open while an administrator edits documents in the workspace. The anonymous socket received, in real time and unfiltered: - `updateAttrs` with `name=WS_LEAK_SECRET_9931` on a block whose `rootID` is a **password-protected** document. - The secret title `WS_SECRET_DOC_7742` of a newly created document. - The create event carrying the notebook (box) name `CritChain` and the document path. No HTTP request was made beyond the WebSocket upgrade; the content arrived over the push channel. ### Impact An anonymous reader (publish mode with auth disabled) or any publish `RoleReader` who merely holds a WebSocket connection open receives a live feed of every edit an administrator makes: block DOM, attributes, titles, notebook names, and document structure, including for password-protected, publish-forbidden, and unpublished documents. This defeats the publish-access and publish-password boundaries entirely for any content edited while the socket is open. The precondition is trivial: an administrator active in the workspace while the anonymous socket is connected. Confidentiality-only (passive disclosure); the channel is receive-only for the reader. Encrypted-notebook content follows the same broadcast path if edited while unlocked. ### Suggested fix Filter broadcasts by session before writing: for any session flagged `isPublish`, apply the same publish-access/publish-ignore/publish-password checks used on the HTTP content path before pushing a content event, or exclude publish sessions from content broadcasts entirely and deliver only the events a publish viewer is authorized to see. The `isPublish` flag is already present on the session; it should gate content, not only the service-closed notice.

Impact

An attacker can connect anonymously to the WebSocket broadcast surface and receive real-time updates of document edits, including those from documents that should be protected by passwords or access restrictions. This results in a complete confidentiality breach of sensitive information without requiring authentication or user interaction.

Summary

CVE-2026-72810 describes a missing authorization vulnerability in SiYuan note-taking software versions prior to v3.7.4. The issue occurs in the WebSocket broadcast mechanism where the publish boundary can be bypassed, allowing unauthenticated attackers to passively receive unfiltered edit events. This includes sensitive content from password-protected or access-restricted documents. The vulnerability has a CVSS 4.0 base score of 9.2, indicating critical severity with network attack vector, no privileges or user interaction required, and high impact on confidentiality and security capabilities.

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Affected software

Description

AI analysisMachine-generated, updated 14 Aug 2026, 12:26 UTC

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