{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-82754",
        "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "state": "PUBLISHED",
        "assignerShortName": "EEF",
        "dateReserved": "2026-08-31T01:00:10.817Z",
        "datePublished": "2026-09-07T22:23:56.762Z",
        "dateUpdated": "2026-09-08T14:41:45.077Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "collectionURL": "https://repo.hex.pm",
                    "cpes": [
                        "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "'Elixir.AshAuthentication.Phoenix.Oauth2Server.Router'",
                        "'Elixir.AshAuthentication.Phoenix.Oauth2Server.ProtocolRouter'"
                    ],
                    "packageName": "ash_authentication_oauth2_server",
                    "packageURL": "pkg:hex/ash_authentication_oauth2_server",
                    "product": "ash_authentication_oauth2_server",
                    "programFiles": [
                        "lib/ash_authentication_phoenix/oauth2_server/router.ex",
                        "lib/ash_authentication_phoenix/oauth2_server/protocol_router.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.AshAuthentication.Phoenix.Oauth2Server.Router':oauth2_server_protocol_routes/1"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Phoenix.Oauth2Server.ProtocolRouter':call/2"
                        }
                    ],
                    "repo": "https://github.com/ash-project/ash_authentication_oauth2_server",
                    "vendor": "ash-project",
                    "versions": [
                        {
                            "lessThan": "0.3.1",
                            "status": "affected",
                            "version": "0.1.0",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "collectionURL": "https://github.com",
                    "cpes": [
                        "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "'Elixir.AshAuthentication.Phoenix.Oauth2Server.Router'",
                        "'Elixir.AshAuthentication.Phoenix.Oauth2Server.ProtocolRouter'"
                    ],
                    "packageName": "ash-project/ash_authentication_oauth2_server",
                    "packageURL": "pkg:github/ash-project/ash_authentication_oauth2_server",
                    "product": "ash_authentication_oauth2_server",
                    "programFiles": [
                        "lib/ash_authentication_phoenix/oauth2_server/router.ex",
                        "lib/ash_authentication_phoenix/oauth2_server/protocol_router.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.AshAuthentication.Phoenix.Oauth2Server.Router':oauth2_server_protocol_routes/1"
                        },
                        {
                            "name": "'Elixir.AshAuthentication.Phoenix.Oauth2Server.ProtocolRouter':call/2"
                        }
                    ],
                    "repo": "https://github.com/ash-project/ash_authentication_oauth2_server",
                    "vendor": "ash-project",
                    "versions": [
                        {
                            "lessThan": "a72972d7ed3eb74c05dfa0653a258ef14454459a",
                            "status": "affected",
                            "version": "855b578037c5ded18e8a6e60f42e56bde4905fae",
                            "versionType": "git"
                        }
                    ]
                }
            ],
            "configurations": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>The routing alias is unconditional. Exploitable impact depends on the deployment applying path-scoped edge controls (WAF, rate limiting, auth-redirect exemptions) to the <code>/oauth</code> prefix, or allow-listing <code>/.well-known</code> as unauthenticated, that the alias then bypasses.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "The routing alias is unconditional. Exploitable impact depends on the deployment applying path-scoped edge controls (WAF, rate limiting, auth-redirect exemptions) to the `/oauth` prefix, or allow-listing `/.well-known` as unauthenticated, that the alias then bypasses."
                        }
                    ],
                    "value": "The routing alias is unconditional. Exploitable impact depends on the deployment applying path-scoped edge controls (WAF, rate limiting, auth-redirect exemptions) to the /oauth prefix, or allow-listing /.well-known as unauthenticated, that the alias then bypasses."
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "cpeMatch": [
                                {
                                    "criteria": "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*",
                                    "versionEndExcluding": "0.3.1",
                                    "versionStartIncluding": "0.1.0",
                                    "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"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>Improper Protection of Alternate Path vulnerability in ash-project ash_authentication_oauth2_server exposes the state-changing OAuth endpoints under an unintended URL prefix, bypassing controls scoped to the canonical prefix.</p>\n<p><code>oauth2_server_protocol_routes/1</code> in <code>AshAuthentication.Phoenix.Oauth2Server.Router</code> forwards the same <code>ProtocolRouter</code> at both the <code>/oauth</code> prefix and the <code>/.well-known</code> prefix. Phoenix <code>forward</code> strips the matched prefix before dispatch, so the full route table answers under both mounts, and <code>POST /register</code>, <code>POST /token</code>, and <code>POST /revoke</code> are reachable as <code>/.well-known/register</code>, <code>/.well-known/token</code>, and <code>/.well-known/revoke</code>. Edge controls such as WAF rules, rate limits, or authentication exemptions written against the <code>/oauth</code> paths, or that allow-list <code>/.well-known</code> as unauthenticated, do not apply to the alias.</p>\n<p>This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "Improper Protection of Alternate Path vulnerability in ash-project ash_authentication_oauth2_server exposes the state-changing OAuth endpoints under an unintended URL prefix, bypassing controls scoped to the canonical prefix.\n\n`oauth2_server_protocol_routes/1` in `AshAuthentication.Phoenix.Oauth2Server.Router` forwards the same `ProtocolRouter` at both the `/oauth` prefix and the `/.well-known` prefix. Phoenix `forward` strips the matched prefix before dispatch, so the full route table answers under both mounts, and `POST /register`, `POST /token`, and `POST /revoke` are reachable as `/.well-known/register`, `/.well-known/token`, and `/.well-known/revoke`. Edge controls such as WAF rules, rate limits, or authentication exemptions written against the `/oauth` paths, or that allow-list `/.well-known` as unauthenticated, do not apply to the alias.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1."
                        }
                    ],
                    "value": "Improper Protection of Alternate Path vulnerability in ash-project ash_authentication_oauth2_server exposes the state-changing OAuth endpoints under an unintended URL prefix, bypassing controls scoped to the canonical prefix.\n\noauth2_server_protocol_routes/1 in AshAuthentication.Phoenix.Oauth2Server.Router forwards the same ProtocolRouter at both the /oauth prefix and the /.well-known prefix. Phoenix forward strips the matched prefix before dispatch, so the full route table answers under both mounts, and POST /register, POST /token, and POST /revoke are reachable as /.well-known/register, /.well-known/token, and /.well-known/revoke. Edge controls such as WAF rules, rate limits, or authentication exemptions written against the /oauth paths, or that allow-list /.well-known as unauthenticated, do not apply to the alias.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1."
                }
            ],
            "impacts": [
                {
                    "capecId": "CAPEC-554",
                    "descriptions": [
                        {
                            "lang": "en",
                            "value": "CAPEC-554 Functionality Bypass"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "attackVector": "NETWORK",
                        "baseScore": 6.3,
                        "baseSeverity": "MEDIUM",
                        "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:N/VI:L/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "LOW",
                        "vulnerabilityResponseEffort": "NOT_DEFINED"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-424",
                            "description": "CWE-424 Improper Protection of Alternate Path",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
                "shortName": "EEF",
                "dateUpdated": "2026-09-07T22:23:56.762Z"
            },
            "references": [
                {
                    "tags": [
                        "vendor-advisory",
                        "related"
                    ],
                    "url": "https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-wwxg-h779-3wf4"
                },
                {
                    "tags": [
                        "related"
                    ],
                    "url": "https://cna.erlef.org/cves/CVE-2026-82754.html"
                },
                {
                    "tags": [
                        "related"
                    ],
                    "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82754"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/ash-project/ash_authentication_oauth2_server/commit/a72972d7ed3eb74c05dfa0653a258ef14454459a"
                }
            ],
            "source": {
                "discovery": "EXTERNAL"
            },
            "title": "ash_authentication_oauth2_server aliases every protocol endpoint under /.well-known, bypassing path-scoped controls"
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-09-08T14:41:33.862078Z",
                                "id": "CVE-2026-82754",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-09-08T14:41:45.077Z"
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        ]
    }
}