CVE-2026-72812Public exploitNetwork attack vectorHinoki check available

Unauthenticated resource amplification via unguarded backlink refresh

Published Aug 14, 2026 · Updated Aug 14, 2026

Missing authorization in SiYuan before 3.7.4 allows remote attackers to trigger persistent server-side writes through backlink refresh. The /api/ref/refreshBacklink route applies CheckAuth alone, accepts an attacker-controlled block ID, flushes transactions, scans references, and enqueues database updates without read-only or per-object checks. Anonymous access requires publish mode with authentication disabled; repeated requests amplify CPU, disk, and database work without exposing or directly corrupting stored content.

CVSS severity6.9
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Missing authorization in SiYuan before 3.7.4 allows remote attackers to trigger persistent server-side writes through backlink refresh. The /api/ref/refreshBacklink route applies CheckAuth alone, accepts an attacker-controlled block ID, flushes transactions, scans references, and enqueues database updates without read-only or per-object checks. Anonymous access requires publish mode with authentication disabled; repeated requests amplify CPU, disk, and database work without exposing or directly corrupting stored content.

The record

CVE
CVE-2026-72812
Published
Aug 14, 2026
Updated
Aug 14, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-862, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 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 <3.7.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SiYuan Note · SiYuanversion=0 <3.7.4

Published CVSS scores

6.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
6.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1499.004Application or System Exploitation

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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