CVE-2026-50159

What it is

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.8 and 11.16.1, Mermaid is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-08-06 22:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-24 16:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.6% in the next 30 days (EPSS).
• Severity: 5.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-08-06 22:17 UTC

Last modified

2026-10-24 16:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-94 · Code injection

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 5.3

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

Passive

Confidentiality

None

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-50159.md and follow it. Check whether this project is affected by CVE-2026-50159. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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