Vulnerability-Lookup

CVE-2026-75866 (GCVE-0-2026-75866)

Vulnerability from cvelistv5 – Published: 2026-08-22 13:52 – Updated: 2026-08-25 19:29

Title

Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client's registered scopes and grant types because no authorization path reads them

Summary

Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client's registered scopes and grant types because no authorization path reads them. Punk::OAuth2::Server::Store registers scopes and grant_types per client and documents both as client registration. token dispatches on the grant_type in the request body, so a client registered for authorization_code alone can ask for client_credentials, and that arm passes the requested scope straight to the minter, which signs it into the at+jwt access token. authorize copies the query scope into the authorization code record without comparing it against the registration, leaving the optional consent hook as the only check between an arbitrary scope and the issued code. redirect_uris on the same client row is read and enforced. A registered client can obtain a correctly signed token carrying any scope it names, and a resource server running Punk::OAuth2::Checker accepts that token and honours the scope. A client registered without a secret authenticates on its client_id alone, so anyone who knows that identifier can request one.

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 19:29 UTC

CWE

CWE-862 - Missing Authorization

Assigner

CPANSec redhat root

References

5 references

URL	Tags
https://metacpan.org/release/LNATION/Punk-OAuth2-…	release-notes
https://metacpan.org/release/LNATION/Punk-OAuth2-…	technical-description
https://datatracker.ietf.org/doc/html/rfc6749#sec…	technical-description
https://datatracker.ietf.org/doc/html/rfc6749#sec…	technical-description
http://www.openwall.com/lists/oss-security/2026/08/22/6

Impacted products

1 product

Vendor	Product	Version	CPE status
		Affected: 0 , ≤ 0.03 (custom)

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-75866

Vulnerability from fkie_nvd - Published: 2026-08-22 14:16 - Updated: 2026-08-26 16:51

Severity

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://datatracker.ietf.org/doc/html/rfc6749#section-3.3
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://datatracker.ietf.org/doc/html/rfc6749#section-5.2
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Punk-OAuth2-0.03/view/lib/Punk/OAuth2/Server/Store.pm
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/LNATION/Punk-OAuth2-0.04/changes
	af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/08/22/6

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
            "Punk::OAuth2::Server"
          ],
          "packageName": "Punk-OAuth2",
          "packageURL": "pkg:cpan/Punk-OAuth2",
          "programFiles": [
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          ],
          "programRoutines": [
            {
              "name": "Punk::OAuth2::Server::token"
            },
            {
              "name": "Punk::OAuth2::Server::authorize"
            }
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    }
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      "value": "Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client\u0027s registered scopes and grant types because no authorization path reads them.\n\nPunk::OAuth2::Server::Store registers scopes and grant_types per client and documents both as client registration. token dispatches on the grant_type in the request body, so a client registered for authorization_code alone can ask for client_credentials, and that arm passes the requested scope straight to the minter, which signs it into the at+jwt access token. authorize copies the query scope into the authorization code record without comparing it against the registration, leaving the optional consent hook as the only check between an arbitrary scope and the issued code. redirect_uris on the same client row is read and enforced.\n\nA registered client can obtain a correctly signed token carrying any scope it names, and a resource server running Punk::OAuth2::Checker accepts that token and honours the scope. A client registered without a secret authenticates on its client_id alone, so anyone who knows that identifier can request one."
    }
  ],
  "id": "CVE-2026-75866",
  "lastModified": "2026-08-26T16:51:19.490",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
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          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
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      "url": "https://datatracker.ietf.org/doc/html/rfc6749#section-3.3"
    },
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      "url": "https://datatracker.ietf.org/doc/html/rfc6749#section-5.2"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Punk-OAuth2-0.03/view/lib/Punk/OAuth2/Server/Store.pm"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/LNATION/Punk-OAuth2-0.04/changes"
    },
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    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
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        {
          "lang": "en",
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        }
      ],
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      "type": "Secondary"
    }
  ]
}

GHSA-CJJX-W599-QF62

Vulnerability from github – Published: 2026-08-22 15:31 – Updated: 2026-08-25 21:31

Details

Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client's registered scopes and grant types because no authorization path reads them.

Punk::OAuth2::Server::Store registers scopes and grant_types per client and documents both as client registration. token dispatches on the grant_type in the request body, so a client registered for authorization_code alone can ask for client_credentials, and that arm passes the requested scope straight to the minter, which signs it into the at+jwt access token. authorize copies the query scope into the authorization code record without comparing it against the registration, leaving the optional consent hook as the only check between an arbitrary scope and the issued code. redirect_uris on the same client row is read and enforced.

A registered client can obtain a correctly signed token carrying any scope it names, and a resource server running Punk::OAuth2::Checker accepts that token and honours the scope. A client registered without a secret authenticates on its client_id alone, so anyone who knows that identifier can request one.

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-75866"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T14:16:33Z",
    "severity": "CRITICAL"
  },
  "details": "Punk::OAuth2::Server versions through 0.03 for Perl issue access tokens outside a client\u0027s registered scopes and grant types because no authorization path reads them.\n\nPunk::OAuth2::Server::Store registers scopes and grant_types per client and documents both as client registration. token dispatches on the grant_type in the request body, so a client registered for authorization_code alone can ask for client_credentials, and that arm passes the requested scope straight to the minter, which signs it into the at+jwt access token. authorize copies the query scope into the authorization code record without comparing it against the registration, leaving the optional consent hook as the only check between an arbitrary scope and the issued code. redirect_uris on the same client row is read and enforced.\n\nA registered client can obtain a correctly signed token carrying any scope it names, and a resource server running Punk::OAuth2::Checker accepts that token and honours the scope. A client registered without a secret authenticates on its client_id alone, so anyone who knows that identifier can request one.",
  "id": "GHSA-cjjx-w599-qf62",
  "modified": "2026-08-25T21:31:21Z",
  "published": "2026-08-22T15:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75866"
    },
    {
      "type": "WEB",
      "url": "https://datatracker.ietf.org/doc/html/rfc6749#section-3.3"
    },
    {
      "type": "WEB",
      "url": "https://datatracker.ietf.org/doc/html/rfc6749#section-5.2"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Punk-OAuth2-0.03/view/lib/Punk/OAuth2/Server/Store.pm"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/LNATION/Punk-OAuth2-0.04/changes"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/22/6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

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.

Action not permitted

CVE-2026-75866 (GCVE-0-2026-75866)

FKIE_CVE-2026-75866

GHSA-CJJX-W599-QF62

Tags

Sightings

Nomenclature