{"id":"CVE-2026-75757","aliases":["EEF-CVE-2026-75757","GHSA-3259-55fp-w94j"],"url":"https://o3.security/vulnerability/CVE-2026-75757","summary":"AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain","details":"Reliance on Cookies without Validation and Integrity Checking vulnerability in ash-project ash_admin lets an attacker who controls a sibling subdomain rebind an admin's session to a different actor, tenant, or authorization mode.\n\nAshAdmin's client JavaScript read its state cookies (tenant, actor_resource, actor_primary_key, actor_action, actor_domain, actor_authorizing, actor_paused) by matching the cookie name with an unanchored regular expression (new RegExp(name + \"=([^;]+)\")) against the whole document.cookie. Any cookie whose name merely ends with the requested name therefore matches, and whichever is serialized first wins. Because cookies are shared across a registrable domain, a compromised sibling subdomain can set a shadowing cookie (for example xactor_authorizing) with Domain=.example.com that flows unvalidated into the admin's LiveSocket connect params. The fix matches cookie names by exact equality.\n\nThis issue affects ash_admin: from 0.9.1 before 1.3.1.","published":"2026-08-31T02:20:17.985Z","modified":"2026-09-01T03:46:12.267782783Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/ash-project/ash_admin/commit/e93a3408a85035e1f90275d02bc2470c96095e56","label":"ash-project/ash_admin@e93a340"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-75757.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-75757"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75757.json"},{"type":"ADVISORY","url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-3259-55fp-w94j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-75757"},{"type":"FIX","url":"https://github.com/ash-project/ash_admin/commit/e93a3408a85035e1f90275d02bc2470c96095e56"},{"type":"PACKAGE","url":"https://github.com/ash-project/ash_admin"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-01T03:46:12.267782783Z"}}