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CVE-2026-75916 siyuan-note CVE debrief

The SiYuan application through version 3.7.3 contains a critical cross-site scripting vulnerability in the '((' block-reference autocomplete hint popup. This vulnerability allows an attacker to inject a self-firing payload that can execute automatically when a victim types '((' followed by a search term that surfaces the crafted block. The payload can lead to arbitrary OS command execution due to Electron windows running with nodeIntegration enabled and no Content Security Policy (CSP). Administrators and users of SiYuan through version 3.7.3 should be aware of this vulnerability and take immediate action to patch or mitigate it. The vulnerability has a CVSS score of 9.3, indicating a critical severity level. The CVE record was published on 2026-08-19T14:17:41.687Z and has not been modified since then. The NVD entry is currently marked as Received. To address this vulnerability, it is essential to apply patches or updates to SiYuan to version 3.7.4 or later. Additionally, implementing a Web Application Firewall (WAF) can help detect and prevent cross-site scripting attacks. Disabling nodeIntegration in Electron windows or implementing a Content Security Policy (CSP) can also mitigate the vulnerability. It is crucial to monitor for suspicious activity and implement logging and incident response plans to minimize potential damage.

Vendor
siyuan-note
Product
siyuan
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-19
Original CVE updated
2026-08-21
Advisory published
2026-08-19
Advisory updated
2026-08-21

Who should care

Administrators and users of SiYuan through version 3.7.3, as well as security teams and incident responders, should be aware of this critical vulnerability and take steps to patch or mitigate it.

Technical summary

The SiYuan application through version 3.7.3 contains a cross-site scripting vulnerability in the '((' block-reference autocomplete hint popup. The genHintItemHTML() function in app/src/protyle/hint/extend.ts concatenates candidate block name, alias, and memo fields into the popup HTML without escaping. An attacker can inject a self-firing payload that executes automatically when a victim types '((' followed by a search term that surfaces the crafted block. The vulnerability escalates to arbitrary OS command execution due to Electron windows running with nodeIntegration enabled and no CSP.

Defensive priority

Administrators and users of SiYuan through version 3.7.3 should prioritize patching or mitigating the cross-site scripting vulnerability that allows for arbitrary OS command execution.

Recommended defensive actions

  • Apply patches or updates to SiYuan to version 3.7.4 or later
  • Implement a Web Application Firewall (WAF) to detect and prevent cross-site scripting attacks
  • Disable nodeIntegration in Electron windows or implement a Content Security Policy (CSP)
  • Monitor for suspicious activity and implement logging and incident response plans
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE-2026-75916 record indicates a critical vulnerability in SiYuan through version 3.7.3, with a CVSS score of 9.3. The vulnerability is due to unescaped block metadata in the hint popup, allowing for cross-site scripting and potential OS command execution. Electron windows run with nodeIntegration enabled and no CSP, which escalates the vulnerability.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-19T14:17:41.687Z and has not been modified since then.