{"id":"CVE-2026-46625","summary":"JavaScript Cookie: Per-instance prototype hijack in assign() enables cookie-attribute injection","details":"JavaScript Cookie is a JavaScript API for handling cookies, client-side. Prior to version 3.0.7, js-cookie's internal assign() helper copies properties with for...in + plain assignment. When the source object is produced by JSON.parse, the JSON object's \"__proto__\" member is an own enumerable property, so the for…in enumerates it and the target[key] = source[key] write triggers the Object.prototype.__proto__ setter on the fresh target ({}). The result is a per-instance prototype hijack: Object.prototype itself is untouched, but the merged attributes object now inherits attacker-controlled keys. Because the consuming set() function then enumerates the merged object with another for...in, every key the attacker placed on the polluted prototype lands in the resulting Set-Cookie string as an attribute pair. The attacker can set domain=, secure=, samesite=, expires=, and path= on cookies whose attributes the developer thought were locked down. This issue has been patched in version 3.0.7.","aliases":["GHSA-qjx8-664m-686j"],"modified":"2026-07-10T03:53:44.404479177Z","published":"2026-06-10T21:18:05.372Z","related":["CGA-4pmp-f695-fjm9"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-1321"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46625.json"},"references":[{"type":"WEB","url":"https://github.com/js-cookie/js-cookie/releases/tag/v3.0.7"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46625.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:33183"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:36625"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-46625"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46625.json"},{"type":"ADVISORY","url":"https://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46625"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2487740"},{"type":"FIX","url":"https://github.com/js-cookie/js-cookie/commit/eb3c40e89731e99b8970faaf35ddad249c6c0020"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/js-cookie/js-cookie","events":[{"introduced":"0"},{"fixed":"eb3c40e89731e99b8970faaf35ddad249c6c0020"},{"fixed":"17bacba0171dd022728d8fdeba3203c60791bf58"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.0.7"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v3.0.5","v3.0.4","v3.0.1","v3.0.0","v3.0.0-rc.4","v3.0.0-rc.3","v3.0.0-rc.2","v3.0.0-rc.1","v3.0.0-rc.0","v3.0.0-beta.4","v3.0.0-beta.3","v3.0.0-beta.2","v3.0.0-beta.1","v3.0.0-beta.0","v2.2.1","v2.2.0","v2.1.4","v2.1.3","v2.1.2","v2.1.1","v2.1.0","v2.0.4","v2.0.3","v2.0.2","v2.0.1","v2.0.0","v2.0.0-beta.1","v1.5.1","v1.5.0","v1.4.1","v1.4.0","v1.3.1","v1.3.0","v1.2.0","v1.1","v1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46625.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}