CVE-2026-54067

CVE-2026-54067 is a critical-severity vulnerability with a CVSS 3.x base score of 9.9. 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

Description

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.

Frequently asked questions

What is CVE-2026-54067?
SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.
How severe is CVE-2026-54067?
CVE-2026-54067 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-54067 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-54067?
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-2026-54067 have an EU (EUVD) identifier?
Yes. CVE-2026-54067 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39123.
When was CVE-2026-54067 published?
CVE-2026-54067 was published on 2026-06-24 and last updated on 2026-06-25.

References

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