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CVE-2026-66395

CRITICAL

CVE-2026-66395 is a critical-severity (CVSS 9.6) Cross-site Scripting (XSS) vulnerability. O3 Security confirms whether CVE-2026-66395 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting…

Published
Jul 27, 2026
Updated
Jul 27, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

Description

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of the affected component has shipped for CVE-2026-66395 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2026-66395 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-66395. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.
O3 Security · Impact-Aware SCA

Is CVE-2026-66395 in your dependencies?

O3 detects CVE-2026-66395 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.