{"id":"CVE-2026-16729","aliases":["GHSA-v3r7-h72x-cjcm"],"url":"https://o3.security/vulnerability/CVE-2026-16729","summary":"undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCookie fields","details":"undici's setCookie function does not fully sanitize cookie attributes. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a domain value is not checked for semicolons and entries in the unparsed array are not sanitized, so attacker-influenced input can inject additional cookie attributes. For example, a domain value containing a semicolon can append attributes such as SameSite, and an unparsed entry can inject attributes such as HttpOnly, without the caller setting them. Applications that pass user-controlled input to these fields, such as multi-tenant or reverse-proxy servers that scope session cookies to a tenant-supplied domain, can have SameSite CSRF protections bypassed, or the Secure, HttpOnly, and SameSite attributes forced, stripped, or overridden. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.","published":"2026-07-29T16:45:57.001Z","modified":"2026-09-18T18:11:38.012920188Z","cvss":{"score":4.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"},"epss":{"score":0.00191,"percentile":0.08948,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"undici","fixedVersion":"6.28.0"},{"ecosystem":"npm","name":"undici","fixedVersion":"7.29.0"},{"ecosystem":"npm","name":"undici","fixedVersion":"8.9.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/16xxx/CVE-2026-16729.json"},{"type":"ADVISORY","url":"https://github.com/nodejs/undici/security/advisories/GHSA-v3r7-h72x-cjcm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16729"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T18:11:38.012920188Z"}}