{"id":"CVE-2026-75757","state":"PUBLISHED","title":"AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain","description":"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.","publishedAt":"2026-08-31T02:20:17.985Z","updatedAt":"2026-08-31T14:50:59.043Z","severity":{"score":8.3,"label":"High","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["ash-project ash_admin"],"affected":[{"vendor":"ash-project","product":"ash_admin","packageName":"ash_admin","packageURL":"pkg:hex/ash_admin","defaultStatus":"unaffected","versions":[{"version":"0.9.1","status":"affected","lessThan":"1.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"programFiles":["assets/js/app.js"],"repo":"https://github.com/ash-project/ash_admin"},{"vendor":"ash-project","product":"ash_admin","packageName":"ash-project/ash_admin","packageURL":"pkg:github/ash-project/ash_admin","defaultStatus":"unaffected","versions":[{"version":"77a43cc4fa04cb59c38fc434568a35a38ecb995a","status":"affected","lessThan":"e93a3408a85035e1f90275d02bc2470c96095e56","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"programFiles":["assets/js/app.js"],"repo":"https://github.com/ash-project/ash_admin"}],"references":["https://github.com/ash-project/ash_admin/security/advisories/GHSA-3259-55fp-w94j","https://cna.erlef.org/cves/CVE-2026-75757.html","https://osv.dev/vulnerability/EEF-CVE-2026-75757","https://github.com/ash-project/ash_admin/commit/e93a3408a85035e1f90275d02bc2470c96095e56"],"weaknesses":["CWE-565"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/75xxx/CVE-2026-75757.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75757","state":"PUBLISHED","datePublished":"2026-08-31T02:20:17.985Z","dateUpdated":"2026-08-31T14:50:59.043Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-30T23:30:01.239Z"},"containers":{"cna":{"title":"AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"ash-project","product":"ash_admin","packageName":"ash_admin","packageURL":"pkg:hex/ash_admin","defaultStatus":"unaffected","versions":[{"version":"0.9.1","status":"affected","lessThan":"1.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"programFiles":["assets/js/app.js"],"repo":"https://github.com/ash-project/ash_admin"},{"vendor":"ash-project","product":"ash_admin","packageName":"ash-project/ash_admin","packageURL":"pkg:github/ash-project/ash_admin","defaultStatus":"unaffected","versions":[{"version":"77a43cc4fa04cb59c38fc434568a35a38ecb995a","status":"affected","lessThan":"e93a3408a85035e1f90275d02bc2470c96095e56","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"programFiles":["assets/js/app.js"],"repo":"https://github.com/ash-project/ash_admin"}],"references":[{"url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-3259-55fp-w94j","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-75757.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-75757","tags":["related"]},{"url":"https://github.com/ash-project/ash_admin/commit/e93a3408a85035e1f90275d02bc2470c96095e56","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.3,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-565","description":"CWE-565 Reliance on Cookies without Validation and Integrity Checking","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-08-31T02:20:17.985Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*","versionEndExcluding":"1.3.1","versionStartIncluding":"0.9.1","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"reporter","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Zach Daniel / Ash Project"},{"lang":"en","type":"coordinator","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-31","descriptions":[{"lang":"en","value":"CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies"}]}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-3259-55fp-w94j","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T14:50:38.307857Z","id":"CVE-2026-75757","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T14:50:59.043Z"}}]}}}