Flowintel Mermaid cross site scripting

Summaryinfo

A vulnerability has been found in Flowintel and classified as problematic. The impacted element is an unknown function of the component Mermaid Handler. The manipulation leads to cross site scripting. This vulnerability is documented as CVE-2026-81753. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Flowintel (the affected version unknown). It has been rated as problematic. This issue affects an unknown part of the component Mermaid Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to 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. Impacted is integrity. The summary by CVE is:

Affected versions of Flowintel render Mermaid blocks contained in stored case notes without sufficiently neutralizing attacker-controlled markup. Because Mermaid note content is persisted and later rendered for other users, an attacker with permission to create or edit a note could store a crafted Mermaid payload that results in JavaScript execution when another user views the affected case note. The patch adds explicit Mermaid detection and HTML escaping around the token content before the generated Mermaid wrapper is returned. It also moves the wrapping logic earlier in page initialization so Markdown instances are protected consistently. Version impacted >= 3.3.0

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-81753 since 08/27/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• Flowintel

Website

• Product: https://github.com/flowintel/flowintel/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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