{"id":"GHSA-84hm-wfh8-c5pg","summary":"sse-channel: SSE Injection via unsanitized event fields","details":"### Impact\n\nImplementations that allows user-provided values to be passed to `event`, `retry` or `id` fields would be susceptible to event spoofing, where an attacker could inject arbitrary messages into the stream.\n\n- **Event Spoofing:** Attacker can inject arbitrary SSE events into the stream\n- **Client-side Manipulation:** Injected events can trigger unintended behavior in frontend JavaScript EventSource listeners\n- **Data Integrity:** Consumers of the SSE stream cannot distinguish injected events from legitimate ones\n\n### Patches\nPatch available in v4.0.1.\n\n### Workarounds\nDo not allow user data to control `event`, `retry` or `id` fields, and if you must - sanitize the input before passing it to `sse-channel`, stripping any newlines. \n\n### Resources\n\nhttps://github.com/rexxars/sse-channel/issues/42","aliases":["CVE-2026-44217"],"modified":"2026-05-13T16:46:23.718132Z","published":"2026-05-05T22:17:02Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-05-05T22:17:02Z","nvd_published_at":"2026-05-12T20:16:42Z","cwe_ids":["CWE-93"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/rexxars/sse-channel/security/advisories/GHSA-84hm-wfh8-c5pg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44217"},{"type":"WEB","url":"https://github.com/rexxars/sse-channel/issues/42"},{"type":"PACKAGE","url":"https://github.com/rexxars/sse-channel"}],"affected":[{"package":{"name":"sse-channel","ecosystem":"npm","purl":"pkg:npm/sse-channel"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.0.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-84hm-wfh8-c5pg/GHSA-84hm-wfh8-c5pg.json","last_known_affected_version_range":"\u003c= 4.0.0"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U"}]}