How severe is CVE-2026-30926?

CVE-2026-30926 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2026-30926 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-30926?

CVE-2026-30926 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-30926?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-30926 have an EU (EUVD) identifier?

Yes. CVE-2026-30926 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10393.

When was CVE-2026-30926 published?

CVE-2026-30926 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-30926

CVE-2026-30926 is a high-severity vulnerability in B3log Siyuan with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10393
Weakness: CWE-862
Affected product: B3log Siyuan
Published: 2026-03-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-30926?: 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.
How severe is CVE-2026-30926?: CVE-2026-30926 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2026-30926 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-30926?: CVE-2026-30926 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-30926?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-30926 have an EU (EUVD) identifier?: Yes. CVE-2026-30926 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10393.
When was CVE-2026-30926 published?: CVE-2026-30926 was published on 2026-03-10 and last updated on 2026-06-17.

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-f9cq-v43p-v523

Affected products (1)

cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*

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