{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.14.0"
              },
              {
                "fixed": "4.15.0"
              },
              {
                "introduced": "5.0.0-rc.10"
              },
              {
                "fixed": "5.0.0-rc.14"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "8badd8f3d618fb864bda1b041c815f7925c35861"
            },
            {
              "fixed": "d6b2be35cf8f0b8ab84e7a934cfb0d91de0a3c17"
            },
            {
              "introduced": "8fa0d9823fbef04aaab517e7ea0f4b17976f1502"
            },
            {
              "fixed": "fea75958a081ed337ceb578396174039694c48df"
            },
            {
              "fixed": "2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba"
            },
            {
              "fixed": "42edcd8ebb13fafbb168f12591d7518ce0611fec"
            },
            {
              "fixed": "64530644f9b37ebb76ca14aeb83a77597a0034b7"
            },
            {
              "fixed": "738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459"
            }
          ],
          "repo": "https://github.com/team-alembic/ash_authentication",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-wc6x-276q-jrf9"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-287"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88952.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "64530644f9b37ebb76ca14aeb83a77597a0034b7"
          },
          {
            "fixed": "*"
          },
          {
            "introduced": "42edcd8ebb13fafbb168f12591d7518ce0611fec"
          },
          {
            "fixed": "*"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "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.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.",
  "id": "CVE-2026-88952",
  "modified": "2026-09-20T11:30:29.974340974Z",
  "published": "2026-09-17T14:15:19.506Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-88952.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-88952"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88952.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-wc6x-276q-jrf9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-88952"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/2bd630eef8b7c8ae1e90e8fd43ba12fbc7e256ba"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/42edcd8ebb13fafbb168f12591d7518ce0611fec"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/64530644f9b37ebb76ca14aeb83a77597a0034b7"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/738bf9f32f2aa0d1bb92ce9ca5c2476cb5710459"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/team-alembic/ash_authentication"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "OAuth2 sign-in attached to an existing account without an email comparison in AshAuthentication"
}