{"id":"EUVD-2026-54244","enisaUuid":"5b5ca83f-3c8d-3e6d-b95c-74f73e723fd5","description":"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\u0027s configuration setters (mermaid.initialize, mermaidAPI.setConfig, and mermaidAPI.updateSiteConfig) merge caller-supplied configuration into Mermaid\u0027s internal config using the assignWithDepth deep-merge helper, which is vulnerable to prototype pollution. This is only exploitable if an application forwards untrusted data directly into one of these configuration entry points, which is outside their documented usage; diagram-supplied configuration (e.g. %%{init: {}}%% or YAML frontmatter) is not affected. This issue is fixed in versions 10.9.8 and 11.16.1.","datePublished":"Aug 6, 2026, 7:59:07 PM","dateUpdated":"Aug 7, 2026, 3:40:29 PM","baseScore":2.4,"baseScoreVersion":"4.0","baseScoreVector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:A/VC:N/VI:L/VA:L/SC:H/SI:H/SA:H","references":"https://github.com/mermaid-js/mermaid/security/advisories/GHSA-c4c3-pg64-4m4v\nhttps://github.com/mermaid-js/mermaid/pull/8022\nhttps://github.com/mermaid-js/mermaid/commit/2cd6dcf735533b323507e3e889ffdea870540b43\nhttps://github.com/mermaid-js/mermaid/commit/c34b07a0815842327e70794d69b0c8c5a1e2a956\nhttps://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1\nhttps://github.com/mermaid-js/mermaid/releases/tag/v10.9.8\n","aliases":"CVE-2026-71438\nGHSA-c4c3-pg64-4m4v\n","assigner":"GitHub_M","epss":0.35,"enisaIdProduct":[{"id":"473d7abc-9018-3154-97db-74ef26e35dc0","product":{"name":"mermaid","vendor":{"name":"mermaid-js"}},"product_version":"11.0.0-alpha.1, \u003c 11.16.1"},{"id":"7b35aaad-fc1a-3bde-8021-93a8b12027f3","product":{"name":"mermaid","vendor":{"name":"mermaid-js"}},"product_version":"\u003c 10.9.8"}],"enisaIdVendor":[{"id":"ec0a243a-5625-35c1-af61-2e618c92bc70","vendor":{"name":"mermaid-js"}}],"enisaIdVulnerability":[{"id":"02921bd6-6607-3c47-9898-ae23d09b1ffc","vulnerability":{"id":"CVE-2026-71438","description":"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\u0027s configuration setters (mermaid.initialize, mermaidAPI.setConfig, and mermaidAPI.updateSiteConfig) merge caller-supplied configuration into Mermaid\u0027s internal config using the assignWithDepth deep-merge helper, which is vulnerable to prototype pollution. This is only exploitable if an application forwards untrusted data directly into one of these configuration entry points, which is outside their documented usage; diagram-supplied configuration (e.g. %%{init: {}}%% or YAML frontmatter) is not affected. This issue is fixed in versions 10.9.8 and 11.16.1.","datePublished":"Aug 6, 2026, 7:59:07 PM","dateUpdated":"Aug 7, 2026, 3:40:29 PM","status":"PUBLISHED","baseScore":2.4,"baseScoreVersion":"4.0","baseScoreVector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:A/VC:N/VI:L/VA:L/SC:H/SI:H/SA:H","references":"https://github.com/mermaid-js/mermaid/security/advisories/GHSA-c4c3-pg64-4m4v\nhttps://github.com/mermaid-js/mermaid/pull/8022\nhttps://github.com/mermaid-js/mermaid/commit/2cd6dcf735533b323507e3e889ffdea870540b43\nhttps://github.com/mermaid-js/mermaid/commit/c34b07a0815842327e70794d69b0c8c5a1e2a956\nhttps://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1\nhttps://github.com/mermaid-js/mermaid/releases/tag/v10.9.8\n","enisa_id":"EUVD-2026-54244\n","assigner":"GitHub_M","epss":0.35,"dataProcessed":"Nov 1, 2026, 7:14:35 AM","vulnerabilityProduct":[{"id":"78dd8e33-4e4f-39e8-8d1f-2d0c60b0330a","product":{"name":"mermaid","vendor":{"name":"mermaid-js"}},"product_version":"\u003c 10.9.8"},{"id":"c4f7c138-bb82-35fd-b74a-474ca4a881ac","product":{"name":"mermaid","vendor":{"name":"mermaid-js"}},"product_version":"11.0.0-alpha.1, \u003c 11.16.1"}],"vulnerabilityVendor":[{"id":"bbbee611-2b08-31e6-a50c-5996cddd6b23","vendor":{"name":"mermaid-js"}}]}},{"id":"9b7c3f7b-c7b5-3008-8c94-fb54c77fbd13","vulnerability":{"id":"GHSA-c4c3-pg64-4m4v","description":"Mermaid configuration APIs allow prototype pollution","datePublished":"Aug 6, 2026, 7:59:10 PM","dateUpdated":"Aug 6, 2026, 7:59:10 PM","baseScore":0.0,"references":"https://github.com/mermaid-js/mermaid/security/advisories/GHSA-c4c3-pg64-4m4v\nhttps://github.com/mermaid-js/mermaid/pull/8022\nhttps://github.com/mermaid-js/mermaid/commit/2cd6dcf735533b323507e3e889ffdea870540b43\nhttps://github.com/mermaid-js/mermaid/commit/c34b07a0815842327e70794d69b0c8c5a1e2a956\nhttps://github.com/mermaid-js/mermaid\nhttps://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1\nhttps://github.com/mermaid-js/mermaid/releases/tag/v10.9.8\n","enisa_id":"EUVD-2026-54244\n","aliases":"GHSA-c4c3-pg64-4m4v\nCVE-2026-71438\n","epss":0.0,"dataProcessed":"Nov 1, 2026, 2:03:49 AM","vulnerabilityProduct":[],"vulnerabilityVendor":[]}}],"enisaIdAdvisory":[]}