{"cve":{"cve_id":"CVE-2026-6658","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":null,"epss_percentile":null,"epss_as_of":null,"description":"A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized `text/vnd.mermaid` output in HTML exports. The `data_mermaid` block in `share/templates/lab/base.html.j2` renders `text/vnd.mermaid` cell output directly into HTML without escaping, enabling attackers to inject arbitrary HTML/JavaScript by breaking out of the `<pre>` tag. This vulnerability impacts any server using nbconvert to render notebooks as HTML, allowing attackers to execute arbitrary JavaScript in the context of users viewing the HTML export.","published_at":"2026-06-26T09:40:30.952000Z","last_modified_at":null,"cvss_v3_score":5.4,"cvss_v3_vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","cvss_v3_severity":"MEDIUM","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-79"],"nvd_references":["https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-28T17:56:06.764790Z","updated_at":"2026-06-28T23:31:02.463961Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"L","value_label":"Low"},{"metric":"I","name":"Integrity","value":"L","value_label":"Low"},{"metric":"A","name":"Availability","value":"N","value_label":"None"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"jupyter","vendor_name":"jupyter","product_slug":"jupyter-jupyter","product_name":"jupyter/jupyter","version_start":"unspecified","version_start_inclusive":true,"version_end":"latest","version_end_inclusive":true,"cpe23_uri":"cve5:jupyter:jupyter-jupyter:unspecified:latest"}],"exploit_refs":[],"news":[],"references":[{"url":"https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-06-26T09:40:30.952000Z","label":"CVE published","source":null}]}