How severe is CVE-2026-34585?

CVE-2026-34585 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-34585 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34585?

CVE-2026-34585 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34585?

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-2026-34585 have an EU (EUVD) identifier?

Yes. CVE-2026-34585 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17685.

When was CVE-2026-34585 published?

CVE-2026-34585 was published on 2026-03-31 and last updated on 2026-06-17.

CVE-2026-34585

CVE-2026-34585 is a high-severity vulnerability in B3log Siyuan with a CVSS 3.x base score of 8.6. 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.6)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-17685
Weakness: CWE-79
Affected product: B3log Siyuan
Published: 2026-03-31
Last modified: 2026-06-17

Description

SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.

Frequently asked questions

What is CVE-2026-34585?: SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.
How severe is CVE-2026-34585?: CVE-2026-34585 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-34585 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34585?: CVE-2026-34585 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34585?: 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-2026-34585 have an EU (EUVD) identifier?: Yes. CVE-2026-34585 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17685.
When was CVE-2026-34585 published?: CVE-2026-34585 was published on 2026-03-31 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in B3log Siyuan

CVE-2026-32938 — Critical (CVSS 9.9): SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the /api/lute/html2BlockDOM on the…
CVE-2026-33670 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.6.2, the /api/file/readDir interface was used to…
CVE-2026-33669 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.6.2, document IDs were retrieved via the…
CVE-2026-32767 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Versions 3.6.0 and below contain an authorization bypass…
CVE-2024-55660 — Critical (CVSS 9.8): SiYuan is a personal knowledge management system. Prior to version 3.1.16, SiYuan's `/api/template/renderSprig`…
CVE-2024-53507 — Critical (CVSS 9.8): A SQL injection vulnerability was discovered in Siyuan 3.1.11 in /getHistoryItems.

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