CVE-2026-87808Public exploitNetwork attack vector

Administrator database reads via unguarded SQL search

Published Sep 9, 2026 · Updated Sep 9, 2026

Protection mechanism failure in SiYuan 3.8.1 and earlier allows remote authenticated users to read the blocks database via SQL search. The fullTextSearchBlock handler forwards method=2 query text to the raw blocks database path without CheckReadonly or CheckReadonlyStatementInBox. Exploitation requires administrator access and a workspace started with --readonly=true; the verified consequence is data disclosure, not modification.

CVSS severity8.7
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Protection mechanism failure in SiYuan 3.8.1 and earlier allows remote authenticated users to read the blocks database via SQL search. The fullTextSearchBlock handler forwards method=2 query text to the raw blocks database path without CheckReadonly or CheckReadonlyStatementInBox. Exploitation requires administrator access and a workspace started with --readonly=true; the verified consequence is data disclosure, not modification.

The record

CVE
CVE-2026-87808
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-693, CAPEC-1, T1213
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

SiYuan Note · SiYuanversion=0 <3.8.2

Published CVSS scores

4.9VulnCheckCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-693Protection Mechanism Failure
CAPEC-1Accessing Functionality Not Properly Constrained by ACLs
T1213Data from Information Repositories

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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