Vulnerability-Lookup

FKIE_CVE-2026-82758

Vulnerability from fkie_nvd - Published: 2026-09-07 23:16 - Updated: 2026-09-08 15:18

Severity

6.3 (Medium) - 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

Summary

Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token. resolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or "" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret. This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.

References

	URL	Tags
	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	https://cna.erlef.org/cves/CVE-2026-82758.html
	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118
	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw
	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	https://osv.dev/vulnerability/EEF-CVE-2026-82758

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.AshAuthentication.Oauth2Server\u0027"
          ],
          "packageName": "ash_authentication_oauth2_server",
          "packageURL": "pkg:hex/ash_authentication_oauth2_server",
          "product": "ash_authentication_oauth2_server",
          "programFiles": [
            "lib/ash_authentication/oauth2_server.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Oauth2Server\u0027:__resolve_secret__!/3"
            }
          ],
          "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": [
            "\u0027Elixir.AshAuthentication.Oauth2Server\u0027"
          ],
          "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/oauth2_server.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Oauth2Server\u0027:__resolve_secret__!/3"
            }
          ],
          "repo": "https://github.com/ash-project/ash_authentication_oauth2_server",
          "vendor": "ash-project",
          "versions": [
            {
              "lessThan": "30a87101871775d27d79f9ad6f29eafa4779e118",
              "status": "affected",
              "version": "855b578037c5ded18e8a6e60f42e56bde4905fae",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or \"\" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1."
    }
  ],
  "id": "CVE-2026-82758",
  "lastModified": "2026-09-08T15:18:50.977",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-82758",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-08T14:40:53.437993Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-07T23:16:53.123",
  "references": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://cna.erlef.org/cves/CVE-2026-82758.html"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82758"
    }
  ],
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary"
    }
  ]
}

CVE-2026-82758 (GCVE-0-2026-82758)

Vulnerability from cvelistv5 – Published: 2026-09-07 22:32 – Updated: 2026-09-08 14:41

Title

ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint

Summary

Severity

6.3 (Medium)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-08 14:40 UTC

CWE

CWE-287 - Improper Authentication

Assigner

EEF mitre root

References

4 references

URL	Tags
https://github.com/ash-project/ash_authentication…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-82758.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-82758	related
https://github.com/ash-project/ash_authentication…	patch

Impacted products

2 products

Vendor	Product	Version
ash-project	ash_authentication_oauth2_server	Affected: 0.1.0 , < 0.3.1 (semver) cpe:2.3:a:ash-project:ash_authentication_oauth2_server::::::::
ash-project	ash_authentication_oauth2_server	Affected: 855b578037c5ded18e8a6e60f42e56bde4905fae , < 30a87101871775d27d79f9ad6f29eafa4779e118 (git) cpe:2.3:a:ash-project:ash_authentication_oauth2_server::::::::

Credits

Peter Ullrich Peter Ullrich Zach Daniel / Ash Project Jonatan Männchen / EEF

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-82758",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-08T14:40:53.437993Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-08T14:41:06.227Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.AshAuthentication.Oauth2Server\u0027"
          ],
          "packageName": "ash_authentication_oauth2_server",
          "packageURL": "pkg:hex/ash_authentication_oauth2_server",
          "product": "ash_authentication_oauth2_server",
          "programFiles": [
            "lib/ash_authentication/oauth2_server.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Oauth2Server\u0027:__resolve_secret__!/3"
            }
          ],
          "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": [
            "\u0027Elixir.AshAuthentication.Oauth2Server\u0027"
          ],
          "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/oauth2_server.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.AshAuthentication.Oauth2Server\u0027:__resolve_secret__!/3"
            }
          ],
          "repo": "https://github.com/ash-project/ash_authentication_oauth2_server",
          "vendor": "ash-project",
          "versions": [
            {
              "lessThan": "30a87101871775d27d79f9ad6f29eafa4779e118",
              "status": "affected",
              "version": "855b578037c5ded18e8a6e60f42e56bde4905fae",
              "versionType": "git"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eReachable only when the server configures an \u003ccode\u003einitial_access_token\u003c/code\u003e (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (\u003ccode\u003enil\u003c/code\u003e, \u003ccode\u003efalse\u003c/code\u003e, or \u003ccode\u003e\"\"\u003c/code\u003e) or an \u003ccode\u003e{:error, _}\u003c/code\u003e for it, rather than a non-empty binary.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Reachable only when the server configures an `initial_access_token` (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (`nil`, `false`, or `\"\"`) or an `{:error, _}` for it, rather than a non-empty binary."
            }
          ],
          "value": "Reachable only when the server configures an initial_access_token (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (nil, false, or \"\") or an {:error, _} for it, rather than a non-empty binary."
        }
      ],
      "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 M\u00e4nnchen / EEF"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eImproper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\u003c/p\u003e\n\u003cp\u003e\u003ccode\u003eresolve_secret/3\u003c/code\u003e in \u003ccode\u003eAshAuthentication.Oauth2Server\u003c/code\u003e (reached through \u003ccode\u003e__resolve_secret__!\u003c/code\u003e) treated any return other than \u003ccode\u003e{:ok, _}\u003c/code\u003e or \u003ccode\u003e:error\u003c/code\u003e from a configured \u003ccode\u003e{module, function, args}\u003c/code\u003e or 2-arity-function secret provider as a valid secret, wrapping \u003ccode\u003enil\u003c/code\u003e, \u003ccode\u003efalse\u003c/code\u003e, or \u003ccode\u003e\"\"\u003c/code\u003e as \u003ccode\u003e{:ok, value}\u003c/code\u003e. When the \u003ccode\u003einitial_access_token\u003c/code\u003e resolves to such an empty value, \u003ccode\u003ePOST /oauth/register\u003c/code\u003e compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as \u003ccode\u003esigning_secret\u003c/code\u003e.\u003c/p\u003e\n\u003cp\u003eThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\n`resolve_secret/3` in `AshAuthentication.Oauth2Server` (reached through `__resolve_secret__!`) treated any return other than `{:ok, _}` or `:error` from a configured `{module, function, args}` or 2-arity-function secret provider as a valid secret, wrapping `nil`, `false`, or `\"\"` as `{:ok, value}`. When the `initial_access_token` resolves to such an empty value, `POST /oauth/register` compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as `signing_secret`.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1."
            }
          ],
          "value": "Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or \"\" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-115",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-115 Authentication 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-287",
              "description": "CWE-287 Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-07T22:32:17.027Z",
        "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "shortName": "EEF"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory",
            "related"
          ],
          "url": "https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw"
        },
        {
          "tags": [
            "related"
          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-82758.html"
        },
        {
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82758"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
    "assignerShortName": "EEF",
    "cveId": "CVE-2026-82758",
    "datePublished": "2026-09-07T22:32:17.027Z",
    "dateReserved": "2026-08-31T01:00:10.817Z",
    "dateUpdated": "2026-09-08T14:41:06.227Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.