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CVE-2026-72803: Missing Authorization in siyuan-note siyuan

0
Medium
Published: 09/03/2026 (09/03/2026, 22:58:29 UTC)
Source: CVE Database V5
Vendor/Project: siyuan-note
Product: siyuan

Description

**CVE:** This vulnerability corresponds to [CVE-2026-72803](https://nvd.nist.gov/vuln/detail/CVE-2026-72803). ### Summary `POST /api/attr/getBlockAttrs` and `POST /api/attr/batchGetBlockAttrs` return a block's full attribute set (IAL) with no publish-access check. Both 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 the block's name, alias, memo, bookmark, tags, and every `custom-*` attribute including for blocks in publish-forbidden and password-protected documents. The batch variant accepts an ID list, making it a bulk extraction primitive. ### Details Neither handler applies a filter: ```go // /api/attr/getBlockAttrs (router line 301) ret.Data = sql.GetBlockAttrs(id) // /api/attr/batchGetBlockAttrs (router line 302) ret.Data = sql.BatchGetBlockAttrs(idList) ``` `sql.GetBlockAttrs` is a direct database read returning the block's entire IAL: `name`, `alias`, `memo`, `bookmark`, `tags`, and any `custom-*` key/value the user has set. Several of these are user-authored free text memos in particular are freeform notes attached to a block so this is document content, not merely structural metadata. `batchGetBlockAttrs` takes an arbitrary list of block IDs in a single request, so an attacker holding a set of block IDs can sweep attributes across the entire workspace in one call. **Guarded-sibling asymmetry.** The sibling metadata endpoint `getBlockInfo` calls `checkBlockPublishAccess(c, id, ret)` before returning; `getBlockAttrs` and `batchGetBlockAttrs` call nothing. Verified at `origin/master`: both handler bodies contain no publish-access, publish-ignore, or readonly-role check, and both routes are registered `CheckAuth` without `CheckAdminRole`. ### Proof of Concept Precondition: publish mode enabled (default port 6808); anonymous when `Publish.Auth.Enable` is `false`, otherwise any publish reader account. A document is marked publish-forbidden (or password-protected) and contains a block with a memo and a custom attribute set. **Single-block disclosure:** ``` POST http://127.0.0.1:6808/api/attr/getBlockAttrs {"id":"<BLOCK_ID_IN_PROTECTED_DOC>"} ``` Returns the block's IAL: `name`, `alias`, `memo`, `bookmark`, `tags`, and all `custom-*` values. **Bulk disclosure:** ``` POST http://127.0.0.1:6808/api/attr/batchGetBlockAttrs {"ids":["<ID1>","<ID2>","<ID3>"]} ``` Returns the attribute sets for every supplied ID in one response, with no per-ID authorization. **Control:** the sibling `getBlockInfo` with the same block ID is refused by `checkBlockPublishAccess`, confirming the boundary is enforced elsewhere and omitted here. ### Impact An anonymous reader (publish mode with auth disabled) or any publish `RoleReader` can read block attributes belonging to publish-forbidden and password-protected documents, including user-authored memos and arbitrary `custom-*` values. The batch endpoint turns this into a bulk primitive: given a set of block IDs, an attacker retrieves attributes across the whole workspace in a single request. Confidentiality-only. ### Suggested fix Call `checkBlockPublishAccess` in `getBlockAttrs` before returning, matching `getBlockInfo`. For `batchGetBlockAttrs`, apply the check per ID and drop unauthorized entries from the response rather than failing the whole batch.

CVSS v4.0

Score 6.9medium

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vuln. Confidentiality
Low
Vuln. Integrity
None
Vuln. Availability
None
Subsq. Confidentiality
Low
Subsq. Integrity
None
Subsq. Availability
None
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

Affected software

siyuan-note

siyuan

Affected versions
>=0 <3.7.4

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 08/12/2026, 19:42:55 UTC

Technical Analysis

CVE-2026-72803 describes a missing authorization vulnerability in SiYuan note-taking software prior to version 3.7.4. The getBlockAttrs and batchGetBlockAttrs API endpoints do not enforce publish-access checks, enabling unauthorized attackers to send POST requests with block IDs and retrieve sensitive block attributes from protected documents. These attributes include names, aliases, memos, and custom fields. The vulnerability has a CVSS 4.0 base score of 6.9, indicating a medium severity impact. No vendor advisory or patch information is currently available, and the software is not a cloud service.

Potential Impact

Attackers can access sensitive metadata from protected documents without authorization, potentially exposing confidential information stored in block attributes. This unauthorized data disclosure could lead to privacy violations or information leakage. There is no indication of privilege escalation or code execution from this vulnerability.

Mitigation Recommendations

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict access to the affected API endpoints where possible and monitor for suspicious POST requests targeting getBlockAttrs and batchGetBlockAttrs endpoints. Avoid exposing these endpoints to untrusted networks.

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Technical Details

Data Version
5.2
Assigner Short Name
VulnCheck
Date Reserved
2026-08-10T15:11:49.794Z
Cvss Version
4.0
State
PUBLISHED

Threat ID: 6a7cc90abf8831d5390772a0

Added to database: 08/12/2026, 19:27:06 UTC

Last enriched: 08/12/2026, 19:42:55 UTC

Last updated: 09/25/2026, 13:47:48 UTC

Views: 52

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