CVE-2026-87810Public exploitNetwork attack vector

Hidden-document match disclosure via unfiltered search counts

Published Sep 9, 2026 · Updated Sep 9, 2026

Information disclosure in SiYuan before 3.8.2 allows remote attackers to infer hidden document matches through publish-mode search. The fullTextSearchBlock handler filters protected blocks only after its search model calculates matched-block, matched-document, and page counts. An unauthenticated publish-mode reader can test chosen terms and learn their presence and aggregate match counts, but not the matching block bodies.

CVSS severity5.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in SiYuan before 3.8.2 allows remote attackers to infer hidden document matches through publish-mode search. The fullTextSearchBlock handler filters protected blocks only after its search model calculates matched-block, matched-document, and page counts. An unauthenticated publish-mode reader can test chosen terms and learn their presence and aggregate match counts, but not the matching block bodies.

The record

CVE
CVE-2026-87810
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-200, T1213
Attack vector
network
Privileges
unauthenticated

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 privilegesunauthenticated

What is affected?

SiYuan Note · SiYuanversion=0 <3.8.2

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
6.9VulnCheck CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
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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