CVE-2026-80218

Sign-in token minted for one resource accepted by another in AshAuthentication

CVSS 4.0 7.6 HIGHCheck source for fixed versionsKEV status unknown

Original advisory

Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.

cve-program · CVE-2026-80218

Published

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. 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. 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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-80218

Published

ash_authentication

https://repo.hex.pm

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "collectionURL": "https://repo.hex.pm",
                    "cpes": [
                        "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "'Elixir.AshAuthentication.Strategy.Password.SignInWithTokenPreparation'",
                        "'Elixir.AshAuthentication.Strategy.WebAuthn.SignInWithTokenPreparation'",
                        "'Elixir.AshAuthentication.Strategy.RememberMe.SignInPreparation'"
                    ],
                    "packageName": "ash_authentication",
                    "packageURL": "pkg:hex/ash_authentication",
                    "product": "ash_authentication",
                    "programFiles": [
                        "lib/ash_authentication/strategies/password/sign_in_with_token_preparation.ex",
                        "lib/ash_authentication/strategies/webauthn/sign_in_with_token_preparation.ex",
                        "lib/ash_authentication/strategies/remember_me/sign_in_preparation.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.Password.SignInWithTokenPreparation':prepare/3"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.WebAuthn.SignInWithTokenPreparation':prepare/3"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.RememberMe.SignInPreparation':prepare/3"
                        }
                    ],
                    "repo": "https://github.com/team-alembic/ash_authentication",
                    "vendor": "team-alembic",
                    "versions": [
                        {
                            "lessThan": "4.15.0",
                            "status": "affected",
                            "version": "3.10.5",
                            "versionType": "semver"
                        },
                        {
                            "lessThan": "5.0.0-rc.14",
                            "status": "affected",
                            "version": "5.0.0-rc.0",
                            "versionType": "semver"
                        }
                    ]
                }

team-alembic/ash_authentication

https://github.com

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "collectionURL": "https://github.com",
                    "cpes": [
                        "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "'Elixir.AshAuthentication.Strategy.Password.SignInWithTokenPreparation'",
                        "'Elixir.AshAuthentication.Strategy.WebAuthn.SignInWithTokenPreparation'",
                        "'Elixir.AshAuthentication.Strategy.RememberMe.SignInPreparation'"
                    ],
                    "packageName": "team-alembic/ash_authentication",
                    "packageURL": "pkg:github/team-alembic/ash_authentication",
                    "product": "ash_authentication",
                    "programFiles": [
                        "lib/ash_authentication/strategies/password/sign_in_with_token_preparation.ex",
                        "lib/ash_authentication/strategies/webauthn/sign_in_with_token_preparation.ex",
                        "lib/ash_authentication/strategies/remember_me/sign_in_preparation.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.Password.SignInWithTokenPreparation':prepare/3"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.WebAuthn.SignInWithTokenPreparation':prepare/3"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Strategy.RememberMe.SignInPreparation':prepare/3"
                        }
                    ],
                    "repo": "https://github.com/team-alembic/ash_authentication",
                    "vendor": "team-alembic",
                    "versions": [
                        {
                            "changes": [
                                {
                                    "at": "2640e1872e1fef4e4606e601bf00102cff784c03",
                                    "status": "unaffected"
                                },
                                {
                                    "at": "7baac243ca651eee127a84d672eee3fcff42e598",
                                    "status": "unaffected"
                                }
                            ],
                            "lessThan": "*",
                            "status": "affected",
                            "version": "eca8cadea0f1595ed2c10a0c177b1da9aa9e5269",
                            "versionType": "git"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON