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CVE-2026-30926

B3log Siyuan broken access control

7.1 HIGHPublic exploitEPSS 0.36%
  1. Published10 Mar 2026

Description

SiYuan is a personal knowledge management system. Prior to 3.5.10, a privilege escalation vulnerability exists in the publish service of SiYuan Note that allows low-privilege publish accounts (RoleReader) to modify notebook content via the /api/block/appendHeadingChildren API endpoint. The endpoint requires only the model.CheckAuth role, which accepts RoleReader sessions, but it does not enforce stricter checks, such as CheckAdminRole or CheckReadonly. This allows remote authenticated publish users with read-only privileges to append new blocks to existing documents, compromising the integrity of stored notes.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityLow
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

Affected products

B3log Siyuan< 3.5.10

Remediation

Fixed in
B3log Siyuan≥ 3.5.10

References

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Frequently asked

Is CVE-2026-30926 being actively exploited?

CVE-2026-30926 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.36%.

How severe is CVE-2026-30926?

CVE-2026-30926 has a CVSS 3.1 base score of 7.1, rated high. EPSS estimates a 0.36% probability of exploitation.

Which products are affected by CVE-2026-30926?

Affected products include B3log Siyuan.

How do I fix CVE-2026-30926?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.5.10 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-30926 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.