{"cve":"CVE-2026-71438","nvd":{"published":"2026-08-06T22:18:30.873","modified":"2026-10-24T15:10:00.190","status":"Awaiting Analysis","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's configuration setters (mermaid.initialize, mermaidAPI.setConfig, and mermaidAPI.updateSiteConfig) merge caller-supplied configuration into Mermaid's 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.","cvss_v4":{"vector":"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","score":2.4},"cvss_v3":null,"cwes":["CWE-1321"],"references":["https://github.com/mermaid-js/mermaid/commit/2cd6dcf735533b323507e3e889ffdea870540b43","https://github.com/mermaid-js/mermaid/commit/c34b07a0815842327e70794d69b0c8c5a1e2a956","https://github.com/mermaid-js/mermaid/pull/8022","https://github.com/mermaid-js/mermaid/releases/tag/mermaid%4011.16.1","https://github.com/mermaid-js/mermaid/releases/tag/v10.9.8"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:34.184483516+00:00"},"epss":{"cve":"CVE-2026-71438","score":0.00353,"percentile":0.28718,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-c4c3-pg64-4m4v","url":"https://osv.dev/vulnerability/GHSA-c4c3-pg64-4m4v","summary":"Mermaid configuration APIs allow prototype pollution","modified":"2026-09-10T03:51:13.780856724Z","packages":[{"ecosystem":"npm","name":"mermaid","purl":"pkg:npm/mermaid","ranges":[">=11.0.0-alpha.1 <11.16.1"],"fixed":["11.16.1"]},{"ecosystem":"npm","name":"mermaid","purl":"pkg:npm/mermaid","ranges":["<10.9.8"],"fixed":["10.9.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}