{"cve":"CVE-2026-33128","nvd":{"published":"2026-03-20T10:16:19.160","modified":"2026-06-17T10:36:59.670","status":"Analyzed","description":"H3 is a minimal H(TTP) framework. In versions prior to 1.15.6 and between 2.0.0 through 2.0.1-rc.14, createEventStream is vulnerable to Server-Sent Events (SSE) injection due to missing newline sanitization in formatEventStreamMessage() and formatEventStreamComment(). An attacker who controls any part of an SSE message field (id, event, data, or comment) can inject arbitrary SSE events to connected clients. This issue is fixed in versions 1.15.6 and 2.0.1-rc.15.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","score":10.0},"cwes":["CWE-93"],"references":["https://github.com/h3js/h3/blob/52c82e18bb643d124b8b9ec3b1f62b081f044611/src/utils/internal/event-stream.ts#L170-L187","https://github.com/h3js/h3/commit/7791538e15ca22437307c06b78fa155bb73632a6","https://github.com/h3js/h3/security/advisories/GHSA-22cc-p3c6-wpvm"],"products":["h3:h3"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-33128","score":0.00583,"percentile":0.47891,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-22cc-p3c6-wpvm","url":"https://osv.dev/vulnerability/GHSA-22cc-p3c6-wpvm","summary":"h3 has a Server-Sent Events Injection via Unsanitized Newlines in Event Stream Fields","modified":"2026-03-20T21:36:02.444400Z","packages":[{"ecosystem":"npm","name":"h3","purl":"pkg:npm/h3","ranges":[">=2.0.0 <2.0.1-rc.15"],"fixed":["2.0.1-rc.15"]},{"ecosystem":"npm","name":"h3","purl":"pkg:npm/h3","ranges":["<1.15.6"],"fixed":["1.15.6"]}]}],"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."]}