Bug 2512224 (CVE-2026-71437)

Summary:	CVE-2026-71437 mermaid: Mermaid: Prototype pollution vulnerability allows potential arbitrary code execution
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	cdrage, rushinde, sdawley
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Mermaid, a JavaScript tool for creating diagrams. This vulnerability, known as prototype pollution, occurs when a specially crafted diagram defines a group with a specific identifier. An attacker who can provide malicious diagram text can exploit this by manipulating core JavaScript object properties, potentially leading to arbitrary code execution or denial of service in the embedding application. This could allow an attacker to gain control over the application or disrupt its operations.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2512870, 2512871, 2512872, 2512874, 2512875, 2512876, 2512877, 2512878, 2512879, 2512880, 2512869, 2512873
Bug Blocks:

Description OSIDB Bzimport 2026-08-06 22:23:15 UTC

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 11.5.0 until 11.16.1, Mermaid Architecture Diagrams are vulnerable to prototype pollution when a diagram defines a group with an id of __proto__. Because the group id is used directly as an object property key without validation, an attacker who can supply diagram text can pollute Object.prototype, potentially affecting the behavior of the embedding application. This issue is fixed in version 11.16.1.