VulnerabilityPublished 12 Aug 2026Updated 14 Aug 2026

CVE-2026-72803: siyuan · Missing Authorization

Affects siyuanSource CVE Database V5

Compare

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 10 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 affected API endpoints where possible and monitor for suspicious POST requests targeting getBlockAttrs and batchGetBlockAttrs endpoints. Avoid exposing these endpoints to untrusted networks.

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.

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.

Summary

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.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

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

Technical details

References

Community reviews

Related threats