Vulnerability · Published Sep 8, 2026 · Assigned by VulDB
CVE-2026-86644star7th showdoc API Page Save Endpoint editormd.js cross site scripting
Low 3.5
In plain English
A low-severity cross-site scripting in showdoc from star7th. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Official description
A vulnerability was determined in star7th showdoc up to 3.9.1. This vulnerability affects unknown code of the file web_src/public/editor.md/editormd.js of the component API Page Save Endpoint. Executing a manipulation can lead to cross site scripting. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 3.9.2 is able to resolve this issue. This patch is called a8ea1520850b4242f395247f72e87e597506cef0. Upgrading the affected component is recommended. The vendor confirms: "The fix [...] sets Mermaid `securityLevel` to `strict`, disables `htmlLabels`, and sanitizes rendered SVG with DOMPurify."
Affected products (as reported)
Weakness: CWE-79, CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
References
- VDB-399755 | star7th showdoc API Page Save Endpoint editormd.js cross site scripting vdb-entry
- VDB-399755 | CTI Indicators (IOB, IOC, TTP, IOA) signature, permissions-required
- CVE-2026-86644 | CVE Analysis and Report third-party-advisory
- Submit #906282 | star7th ShowDoc 3.7.1 - 3.9.1 Cross Site Scripting third-party-advisory
- https://gist.github.com/saDL0w/36a72a076e9ab24408a3d27582e778b2 exploit
- https://github.com/star7th/showdoc/commit/a8ea1520850b4242f395247f72e87e597506cef0 patch
- https://github.com/star7th/showdoc/releases/tag/v3.9.2 patch
- https://github.com/star7th/showdoc/ product