How severe is CVE-2026-39846?

CVE-2026-39846 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-39846 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39846?

CVE-2026-39846 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39846?

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

Does CVE-2026-39846 have an EU (EUVD) identifier?

Yes. CVE-2026-39846 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19973.

When was CVE-2026-39846 published?

CVE-2026-39846 was published on 2026-04-07 and last updated on 2026-06-17.

CVE-2026-39846

CVE-2026-39846 is a critical-severity vulnerability in B3log Siyuan with a CVSS 3.x base score of 9.0. 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: Critical (CVSS 3.x base score 9.0)
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-19973
Weakness: CWE-79
Affected product: B3log Siyuan
Published: 2026-04-07
Last modified: 2026-06-17

Description

SiYuan is a personal knowledge management system. Prior to 3.6.4, a malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. This vulnerability is fixed in 3.6.4.

Frequently asked questions

What is CVE-2026-39846?: SiYuan is a personal knowledge management system. Prior to 3.6.4, a malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. This vulnerability is fixed in 3.6.4.
How severe is CVE-2026-39846?: CVE-2026-39846 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39846 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39846?: CVE-2026-39846 affects B3log Siyuan. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39846?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-39846 have an EU (EUVD) identifier?: Yes. CVE-2026-39846 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19973.
When was CVE-2026-39846 published?: CVE-2026-39846 was published on 2026-04-07 and last updated on 2026-06-17.

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-phhp-9rm9-6gr2

Affected products (1)

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

More vulnerabilities in B3log Siyuan

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