{"id":"EEF-CVE-2026-75757","summary":"AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain","details":"## Summary\n\nReliance 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.","aliases":["CVE-2026-75757","GHSA-3259-55fp-w94j"],"modified":"2026-09-08T03:30:11.378207510Z","published":"2026-08-31T02:20:17.985Z","database_specific":{"capec_ids":["CAPEC-31"],"cpe_ids":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-565"]},"references":[{"type":"ADVISORY","url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-3259-55fp-w94j"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-75757.html"},{"type":"FIX","url":"https://github.com/ash-project/ash_admin/commit/e93a3408a85035e1f90275d02bc2470c96095e56"},{"type":"PACKAGE","url":"https://hex.pm/packages/ash_admin"}],"affected":[{"package":{"name":"ash_admin","ecosystem":"Hex","purl":"pkg:hex/ash_admin"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.9.1"},{"fixed":"1.3.1"}]}],"versions":["0.10.0","0.10.1","0.10.10","0.10.10-rc.0","0.10.10-rc.1","0.10.11","0.10.12","0.10.2","0.10.3","0.10.4","0.10.5","0.10.6","0.10.7","0.10.8","0.10.9","0.11.0","0.11.1","0.11.10","0.11.11","0.11.2","0.11.3","0.11.4","0.11.5","0.11.6","0.11.7","0.11.8","0.11.9","0.12.0","0.12.1","0.12.2","0.12.3","0.12.4","0.12.5","0.12.6","0.13.0","0.13.1","0.13.10","0.13.11","0.13.12","0.13.13","0.13.14","0.13.15","0.13.16","0.13.17","0.13.18","0.13.19","0.13.2","0.13.20","0.13.21","0.13.22","0.13.23","0.13.24","0.13.25","0.13.26","0.13.3","0.13.4","0.13.5","0.13.6","0.13.7","0.13.8","0.13.9","0.14.0","0.9.1","0.9.2","0.9.3","0.9.4","0.9.5","0.9.6","0.9.7","0.9.8","1.0.0-rc.0","1.1.0","1.2.0","1.3.0"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-75757.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/ash-project/ash_admin","events":[{"introduced":"77a43cc4fa04cb59c38fc434568a35a38ecb995a"},{"fixed":"e93a3408a85035e1f90275d02bc2470c96095e56"}]}],"versions":["v1.3.0","v1.2.0","v1.1.0","v0.14.0","v0.13.26","v0.13.25","v0.13.24","v0.13.23","v0.13.22","v0.13.21","v0.13.20","v0.13.19","v0.13.18","v0.13.17","v0.13.16","v0.13.15","v0.13.14","v0.13.13","v0.13.12","v0.13.11","v0.13.10","v0.13.9","v0.13.8","v0.13.7","v0.13.6","v0.13.5","v0.13.4","v0.13.3","v0.13.2","v0.13.0","v0.12.6","v0.12.5","v0.12.4","v0.12.3","v0.12.2","v0.12.1","v0.12.0","v0.11.11","v0.11.10","v0.11.9","v0.11.8","v0.11.7","v0.11.6","v0.11.4","v0.11.3","v0.11.2","v0.11.1","v0.10.10","v0.10.10-rc.1","v0.10.10-rc.0","v0.10.9","v0.10.8","v0.10.7","v0.10.6","v0.10.5","v0.10.4","v0.10.3","v0.10.2","v0.10.1","v0.10.0","v0.9.8","v0.9.7","v0.9.6","v0.9.5","v0.9.4","v0.9.2","v0.9.1"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-75757.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N"}],"credits":[{"name":"Peter Ullrich","type":"FINDER"},{"name":"Peter Ullrich","type":"REPORTER"},{"name":"Zach Daniel / Ash Project","type":"REMEDIATION_DEVELOPER"},{"name":"Jonatan Männchen / EEF","type":"COORDINATOR"}]}