VulnerabilityPublished 12 Aug 2026Updated 14 Aug 2026

CVE-2026-72805: siyuan · Missing Authorization

Affects siyuanSource CVE Database V5

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Not known to be exploited · CVSS 6.9 Medium : upgrade to 3.7.4 when convenient.

Data as of 9 Nov 2026, 23:24 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 22% 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:L/VI:N/VA:N/SC:L/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: Low
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
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 12 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 9 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 and siyuan-note/siyuan to 3.7.4.

Affected software

Product	Affected	Fixed in
siyuan-notesiyuan	Affected <3.7.4	Fixed in 3.7.4
GitHubsiyuan-note/siyuan`pkg:github/siyuan-note/siyuan`Other threats	Affected <3.7.4	Fixed in 3.7.4

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AI-suggested

Users should upgrade to SiYuan version 3.7.4 or later once available, as this version presumably addresses the missing authorization checks. Until a patch is confirmed, restrict access to the affected endpoints and monitor for unauthorized access attempts if possible.

Description

**CVE:** This vulnerability corresponds to [CVE-2026-72805](https://nvd.nist.gov/vuln/detail/CVE-2026-72805). ### Summary Three block endpoints return document content snippets and metadata without any publish-access check, while their sibling `getBlockInfo` which returns comparable data does enforce one. All three are `CheckAuth`-only, so they are reachable by the publish `RoleReader` token and by the anonymous account when `Publish.Auth.Enable` is `false`. An anonymous reader supplying a block ID receives content and metadata belonging to publish-forbidden and password-protected documents. ### Details `getBlockInfo` (`kernel/api/block.go`) gates on the publish boundary: ```go if !checkBlockPublishAccess(c, id, ret) { return } ``` The following siblings in the same file perform no equivalent check: | Endpoint | Returns | Publish check | |---|---|---| | `getBlockInfo` | root/title/path metadata | `checkBlockPublishAccess`: present | | `getBlockBreadcrumb` | `BlockPath.Name` : root document title plus every ancestor block's content snippet | none | | `getRefText` | the block's reference/anchor text (document content) | none | | `getBlockTreeInfos` | root/title/path metadata for arbitrary block IDs | none | `getBlockBreadcrumb` returns the full ancestor chain including each ancestor block's content snippet, and `getRefText` returns block anchor text both are document content, not just metadata. `getBlockTreeInfos` returns root/title/path for any caller-supplied ID set via `model.GetBlockTreeInfosInBox(...)` with no gate. `getBlockBreadcrumb` and `getRefText` additionally accept a client-supplied notebook argument that routes to the `*InBox` variants, so the same unguarded path applies to encrypted-notebook reads while the notebook is unlocked. The correct primitive already exists in the codebase and is used by `getBlockInfo`; these three handlers simply do not call it. ### Proof of Concept Precondition: publish mode enabled (default port 6808); anonymous when `Publish.Auth.Enable` is `false`, otherwise any publish reader account. A document `D` is marked publish-forbidden (or password-protected) and contains a block `BLOCK_ID` under a heading with distinctive content. **Control: the gated sibling correctly refuses:** ``` POST http://127.0.0.1:6808/api/block/getBlockInfo {"id":"BLOCK_ID"} ``` Blocked by `checkBlockPublishAccess`. **Disclosure: the ungated siblings return the data anyway:** ``` POST http://127.0.0.1:6808/api/block/getBlockBreadcrumb {"id":"BLOCK_ID"} → ancestor chain including the forbidden document's title and ancestor block content snippets POST http://127.0.0.1:6808/api/block/getRefText {"id":"BLOCK_ID"} → the block's reference/anchor text (content of the forbidden document) POST http://127.0.0.1:6808/api/block/getBlockTreeInfos {"ids":["BLOCK_ID"]} → root ID, title, and path for the forbidden document ``` Verified by code inspection at `origin/master` (`eef10568`): `getBlockInfo` contains the `checkBlockPublishAccess` call; `getBlockBreadcrumb`, `getRefText`, and `getBlockTreeInfos` contain no publish-access, publish-ignore, or readonly-role check in their bodies. ### Impact An anonymous reader (publish mode with auth disabled) or any publish `RoleReader` can read, for documents explicitly excluded from publishing or protected by a publish password: - the document title and full ancestor chain, including ancestor block content snippets (`getBlockBreadcrumb`); - block reference/anchor text, i.e. document content (`getRefText`); - root ID, title, and path metadata for arbitrary block IDs (`getBlockTreeInfos`). Because `getBlockBreadcrumb` and `getRefText` accept a notebook argument routing to the `*InBox` variants, the same disclosure applies to encrypted notebooks while unlocked. Confidentiality-only; the precondition is a block ID, obtainable from other reader-reachable endpoints. ### Suggested fix Call `checkBlockPublishAccess` (as `getBlockInfo` does) in `getBlockBreadcrumb`, `getRefText`, and `getBlockTreeInfos` before returning data for `getBlockTreeInfos`, apply it per ID and drop unauthorized entries. Confirm the `*InBox` variants (`GetBlockRefTextInBox`, `BuildBlockBreadcrumbInBox`) enforce the same boundary so the notebook-argument path is covered.

Impact

The vulnerability allows unauthorized disclosure of protected document content and metadata. Attackers can access document titles, snippets of ancestor block content, reference text, and path metadata without proper authorization. This could lead to information leakage of sensitive or confidential documents that are intended to be restricted or password-protected. There is no indication of privilege escalation or modification capabilities. No known exploits in the wild have been reported.

Summary

CVE-2026-72805 describes a missing authorization vulnerability in SiYuan note-taking software versions prior to 3.7.4. The vulnerability affects the getBlockBreadcrumb, getRefText, and getBlockTreeInfos API endpoints, which fail to enforce publish-access checks. As a result, unauthorized users, including anonymous readers or users with publish RoleReader permissions, can retrieve sensitive document information such as titles, content snippets from ancestor blocks, reference text, and path metadata for documents that are publish-forbidden or password-protected. This exposure compromises confidentiality of protected documents.

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Affected software

Description

AI analysisMachine-generated, updated 12 Aug 2026, 19:42 UTC

Technical details

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