{"id":"CVE-2026-88952","title":"Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker to be signed in as another user by linking an OAuth2 identity to an account that is not theirs.\n\nAshAuthentication.Strategy.OAuth2.UserResolver.re…","summary":"Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker to be signed in as another user by linking an OAuth2 identity to an account that is not theirs.\n\nAshAuthentication.Strategy.OAuth2.UserResolver.re…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","cwe":["CWE-287"],"vendor":"team-alembic","product":"ash_authentication","affected":["ash_authentication >= 4.14.0 < 4.15.0","ash_authentication >= 5.0.0-rc.10 < 5.0.0-rc.14","team-alembic/ash_authentication >= 64530644f9b37ebb76ca14aeb83a77597a0034b7 < *","team-alembic/ash_authentication >= 42edcd8ebb13fafbb168f12591d7518ce0611fec < *"],"published":"2026-09-17","updated":"2026-09-18","sourceUpdated":"2026-09-18T18:16:18.527","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88952","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-88952.html","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/42edcd8ebb13fafbb168f12591d7518ce0611fec","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/64530644f9b37ebb76ca14aeb83a77597a0034b7","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/commit/738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-wc6x-276q-jrf9","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-88952","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"tags":["nvd","cve.org"],"epss":0.00435,"epssPercentile":0.37194,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-17T19:32:22.090404Z"},"cvssSource":"cna","ingestedAt":"2026-09-17T15:20:39.001Z","slug":"CVE-2026-88952","body":"## Overview\n\nImproper Authentication vulnerability in team-alembic AshAuthentication allows an attacker to be signed in as another user by linking an OAuth2 identity to an account that is not theirs.\n\nAshAuthentication.Strategy.OAuth2.UserResolver.resolve/3 matches an existing account using the register action's upsert_identity keys, then gates linking the incoming provider identity to it on email_trusted?/2, which reads only the provider's email_verified boolean and never compares the provider's email value with the matched account's email. That gate assumes the account was matched by its email field, so under any other upsert_identity it is vacuous and an attacker presenting their own verified email is attached to, and issued a session for, an account matched on some other attribute. The same unguarded gate applies in OAuth2.SignInPreparation on the registration_enabled? false path, where the account is matched by the sign-in action's read filter instead. The upsert also rewrites the matched account's email to the attacker's address, so later account recovery reaches the attacker rather than the owner.\n\nThis issue affects ash_authentication: from 4.14.0 before 4.15.0 and from 5.0.0-rc.10 before 5.0.0-rc.14.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}