{"id":"CVE-2026-47675","aliases":["GHSA-3hrh-pfw6-9m5x"],"url":"https://o3.security/vulnerability/CVE-2026-47675","summary":"Hono: Cookie helper does not sanitize sameSite and priority, allowing Set-Cookie injection","details":"Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \\r, \\n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.","published":"2026-05-28T15:28:23.458Z","modified":"2026-08-12T03:51:12.832122677Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},"epss":{"score":0.00216,"percentile":0.12327,"asOf":"2026-08-20"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"hono","fixedVersion":"4.12.21"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47675.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-3hrh-pfw6-9m5x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47675"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:12.832122677Z"}}