Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker holding a sign-in token for one authenticated resource to be signed in as a user of a different resource.
\nAshAuthentication.Strategy.Password.SignInWithTokenPreparation.extract_primary_keys_from_subject/2 parses the JWT sub claim (for example user?id=1) with URI.parse/1 and keeps only its query string, discarding the path segment that names the subject the token was issued for. Nothing else restores that binding: AshAuthentication.Jwt.verify/3 checks the signature, exp, nbf, jti and the library-version claims, the purpose check only requires sign_in, and the remaining comparison is over primary-key field names, which are identical across resources. The WebAuthn sign-in and remember-me preparations carry copies of the same helper and drop the path in the same way. The magic link sign-in path pins the subject name against the resource and is not affected.
This issue affects ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
"},{"base64":false,"type":"text/markdown","value":"Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker holding a sign-in token for one authenticated resource to be signed in as a user of a different resource.\n\n`AshAuthentication.Strategy.Password.SignInWithTokenPreparation.extract_primary_keys_from_subject/2` parses the JWT `sub` claim (for example `user?id=1`) with `URI.parse/1` and keeps only its query string, discarding the path segment that names the subject the token was issued for. Nothing else restores that binding: `AshAuthentication.Jwt.verify/3` checks the signature, `exp`, `nbf`, `jti` and the library-version claims, the purpose check only requires `sign_in`, and the remaining comparison is over primary-key field names, which are identical across resources. The WebAuthn sign-in and remember-me preparations carry copies of the same helper and drop the path in the same way. The magic link sign-in path pins the subject name against the resource and is not affected.\n\nThis issue affects ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."}],"value":"Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker holding a sign-in token for one authenticated resource to be signed in as a user of a different resource.\n\nAshAuthentication.Strategy.Password.SignInWithTokenPreparation.extract_primary_keys_from_subject/2 parses the JWT sub claim (for example user?id=1) with URI.parse/1 and keeps only its query string, discarding the path segment that names the subject the token was issued for. Nothing else restores that binding: AshAuthentication.Jwt.verify/3 checks the signature, exp, nbf, jti and the library-version claims, the purpose check only requires sign_in, and the remaining comparison is over primary-key field names, which are identical across resources. The WebAuthn sign-in and remember-me preparations carry copies of the same helper and drop the path in the same way. The magic link sign-in path pins the subject name against the resource and is not affected.\n\nThis issue affects ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14."}],"impacts":[{"capecId":"CAPEC-151","descriptions":[{"lang":"en","value":"CAPEC-151 Identity Spoofing"}]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":7.6,"baseSeverity":"HIGH","privilegesRequired":"LOW","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:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-287","description":"CWE-287 Improper Authentication","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-17T13:09:25.585Z","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","shortName":"EEF"},"references":[{"tags":["vendor-advisory","related"],"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-3pr8-f99q-86hp"},{"name":"EEF CNA record for CVE-2026-80218","tags":["related"],"url":"https://cna.erlef.org/cves/CVE-2026-80218.html"},{"name":"OSV record EEF-CVE-2026-80218","tags":["related"],"url":"https://osv.dev/vulnerability/EEF-CVE-2026-80218"},{"name":"Introducing commit eca8cad in team-alembic/ash_authentication","tags":["related"],"url":"https://github.com/team-alembic/ash_authentication/commit/eca8cadea0f1595ed2c10a0c177b1da9aa9e5269"},{"name":"Fix commit 2640e18 in team-alembic/ash_authentication","tags":["patch"],"url":"https://github.com/team-alembic/ash_authentication/commit/2640e1872e1fef4e4606e601bf00102cff784c03"},{"name":"Fix commit 7baac24 in team-alembic/ash_authentication","tags":["patch"],"url":"https://github.com/team-alembic/ash_authentication/commit/7baac243ca651eee127a84d672eee3fcff42e598"}],"source":{"discovery":"INTERNAL"},"title":"Sign-in token minted for one resource accepted by another in AshAuthentication"}},"cveMetadata":{"assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","assignerShortName":"EEF","cveId":"CVE-2026-80218","datePublished":"2026-09-17T13:09:25.585Z","dateReserved":"2026-09-11T18:30:01.333Z","dateUpdated":"2026-09-17T13:09:25.585Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"}