CVE-2026-86644

Deferred Deferred - Pending Action

Cross-Site Scripting in Star7th ShowDoc

Publication date: 2026-09-08

Last updated on: 2026-09-08

Assigner: VulDB

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."

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-08

Last Modified

2026-09-08

Generated

2026-09-29

AI Q&A

2026-09-09

EPSS Evaluated

2026-09-27

NVD

CVE-2026-86644

Affected Vendors & Products

Vendor	Product	Version / Range
star7th	showdoc	to 3.9.1 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-94	The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Attack-Flow Graph

Executive Summary

This vulnerability is a cross-site scripting (XSS) issue in star7th showdoc versions up to 3.9.1. It exists in the file web_src/public/editor.md/editormd.js and is triggered via the API Page Save Endpoint. An attacker can exploit this by manipulating input to inject malicious scripts into web pages.

Detection Guidance

To detect this vulnerability, check if your system is running star7th showdoc version 3.9.1 or earlier. Inspect the file web_src/public/editor.md/editormd.js for potential XSS vulnerabilities. No specific commands are provided in the context.

Impact Analysis

The vulnerability allows remote attackers to execute malicious scripts in a user's browser when they access a compromised page. This could lead to theft of session cookies, account takeover, or defacement of web pages. Users of affected versions are at risk if they interact with untrusted content.

Compliance Impact

This XSS vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles and HIPAA's security requirements for protected health information. Organizations may face compliance breaches if exploited, resulting in legal and financial penalties.

Mitigation Strategies

Upgrade star7th showdoc to version 3.9.2 or later. The patch sets Mermaid securityLevel to strict, disables htmlLabels, and sanitizes SVG with DOMPurify. This resolves the XSS vulnerability.

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