Vulnerability-Lookup

CVE-2026-55982 (GCVE-0-2026-55982)

Vulnerability from cvelistv5 – Published: 2026-08-13 16:44 – Updated: 2026-08-14 17:42

Title

OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes

Summary

OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes

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: poc Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-14 17:42 UTC

CWE

CWE-200

Assigner

Gitea

References

3 references

URL	Tags
https://github.com/go-gitea/gitea/security/adviso…	vendor-advisory
https://github.com/go-gitea/gitea/releases/tag/v1.27.0	release-notes
https://blog.gitea.com/gitea-1.27.0-is-released/	release-notes

Impacted products

1 product

Vendor	Product	Version
Gitea	Gitea Open Source Git Server	Affected: 1.26.2 (semver)

Credits

ybsun0215

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 9.1,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-55982",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-14T17:42:04.816118Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-14T17:42:09.138Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-mg4f-x9v4-6h2p"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Gitea Open Source Git Server",
          "vendor": "Gitea",
          "versions": [
            {
              "status": "affected",
              "version": "1.26.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "ybsun0215"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes"
        }
      ],
      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-200",
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              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-08-13T16:44:40.177Z",
        "orgId": "88ee5874-cf24-4952-aea0-31affedb7ff2",
        "shortName": "Gitea"
      },
      "references": [
        {
          "name": "GitHub Security Advisory",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-mg4f-x9v4-6h2p"
        },
        {
          "name": "Gitea v1.27.0 Release",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/go-gitea/gitea/releases/tag/v1.27.0"
        },
        {
          "name": "Gitea v1.27.0 Release Blog Post",
          "tags": [
            "release-notes"
          ],
          "url": "https://blog.gitea.com/gitea-1.27.0-is-released/"
        }
      ],
      "title": "OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes",
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        "engine": "cvelib 1.8.0"
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    }
  },
  "cveMetadata": {
    "assignerOrgId": "88ee5874-cf24-4952-aea0-31affedb7ff2",
    "assignerShortName": "Gitea",
    "cveId": "CVE-2026-55982",
    "datePublished": "2026-08-13T16:44:40.177Z",
    "dateReserved": "2026-07-08T09:19:08.021Z",
    "dateUpdated": "2026-08-14T17:42:09.138Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-55982",
      "date": "2026-08-14",
      "epss": "0.0017",
      "percentile": "0.06692"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-55982\",\"sourceIdentifier\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\",\"published\":\"2026-08-13T17:17:24.750\",\"lastModified\":\"2026-08-13T17:17:24.750\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes\"}],\"affected\":[{\"source\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\",\"affectedData\":[{\"vendor\":\"Gitea\",\"product\":\"Gitea Open Source Git Server\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"1.26.2\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{},\"weaknesses\":[{\"source\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-200\"}]}],\"references\":[{\"url\":\"https://blog.gitea.com/gitea-1.27.0-is-released/\",\"source\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\"},{\"url\":\"https://github.com/go-gitea/gitea/releases/tag/v1.27.0\",\"source\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\"},{\"url\":\"https://github.com/go-gitea/gitea/security/advisories/GHSA-mg4f-x9v4-6h2p\",\"source\":\"88ee5874-cf24-4952-aea0-31affedb7ff2\"}]}}"
  }
}

GHSA-MG4F-X9V4-6H2P

Vulnerability from github – Published: 2026-07-21 20:42 – Updated: 2026-07-21 20:42

Summary

Gitea: OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes

Details

Summary

The OIDC userinfo endpoint (GET /login/oauth/userinfo) accepts Gitea API tokens as bearer credentials but does not enforce API token scopes before returning identity claims.

A personal access token scoped only to read:misc can successfully retrieve user information from the OIDC userinfo endpoint, even though the same token is denied access to user-related REST API endpoints that enforce scope checks.

As a result, identity information remains accessible through the OIDC endpoint regardless of the scopes assigned to the API token.

Details

Gitea supports scoped personal access tokens and enforces scope checks on user-related REST API endpoints.

For example, a token scoped only to read:misc is denied access to endpoints such as:

Endpoint	Required Scope
`GET /api/v1/user`	`read:user`
`GET /api/v1/user/emails`	`read:user`
`GET /api/v1/user/orgs`	`read:organization`

Requests to these endpoints return:

403 Forbidden

with a scope-related error.

However, the same read:misc token can be supplied as a bearer credential to:

GET /login/oauth/userinfo
Authorization: Bearer <token>

and receives a successful response containing identity claims.

Observed claims include:

email
groups

The groups claim contains organization and team membership information associated with the authenticated user.

This behavior indicates that the OIDC userinfo endpoint accepts API tokens but does not apply scope restrictions before returning identity claims.

PoC

PoC Details

Proof-of-concept code: https://anonymous.4open.science/r/Gitea_PoC-EC93/3_poc_oidc_userinfo_scope_bypass

Reproduction Steps

Create a personal access token with only the following scope:

read:misc

Verify that the token cannot access user-related REST API endpoints:

GET /api/v1/user
GET /api/v1/user/emails
GET /api/v1/user/orgs

Each request returns:

403 Forbidden

Send the same token to the OIDC userinfo endpoint:

GET /login/oauth/userinfo
Authorization: Bearer <read-misc-token>

Observe that the request succeeds and returns identity claims, for example:

{
  "email": "user@example.com",
  "groups": [
    ...
  ]
}

Impact

Holders of narrowly scoped API tokens can obtain identity information through the OIDC userinfo endpoint regardless of the scopes assigned to the token.

The issue does not provide access to repositories, issues, pull requests, administrative functionality, or data belonging to other users.

Impact is limited to disclosure of identity information associated with the authenticated user. However, it weakens the authorization boundary established by API token scopes because identity claims remain accessible even when the token lacks user- or organization-related scopes.

Severity

5.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "code.gitea.io/gitea"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.27.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55982"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-21T20:42:05Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThe OIDC userinfo endpoint (`GET /login/oauth/userinfo`) accepts Gitea API tokens as bearer credentials but does not enforce API token scopes before returning identity claims.\n\nA personal access token scoped only to `read:misc` can successfully retrieve user information from the OIDC userinfo endpoint, even though the same token is denied access to user-related REST API endpoints that enforce scope checks.\n\nAs a result, identity information remains accessible through the OIDC endpoint regardless of the scopes assigned to the API token.\n\n### Details\n\nGitea supports scoped personal access tokens and enforces scope checks on user-related REST API endpoints.\n\nFor example, a token scoped only to `read:misc` is denied access to endpoints such as:\n\n| Endpoint | Required Scope |\n|----------|----------------|\n| `GET /api/v1/user` | `read:user` |\n| `GET /api/v1/user/emails` | `read:user` |\n| `GET /api/v1/user/orgs` | `read:organization` |\n\nRequests to these endpoints return:\n\n```http\n403 Forbidden\n```\n\nwith a scope-related error.\n\nHowever, the same `read:misc` token can be supplied as a bearer credential to:\n\n```http\nGET /login/oauth/userinfo\nAuthorization: Bearer \u003ctoken\u003e\n```\n\nand receives a successful response containing identity claims.\n\nObserved claims include:\n\n- `email`\n- `groups`\n\nThe `groups` claim contains organization and team membership information associated with the authenticated user.\n\nThis behavior indicates that the OIDC userinfo endpoint accepts API tokens but does not apply scope restrictions before returning identity claims.\n\n### PoC\n\n#### PoC Details\n\nProof-of-concept code: \nhttps://anonymous.4open.science/r/Gitea_PoC-EC93/3_poc_oidc_userinfo_scope_bypass\n\n#### Reproduction Steps\n\n1. Create a personal access token with only the following scope:\n\n```text\nread:misc\n```\n\n2. Verify that the token cannot access user-related REST API endpoints:\n\n```http\nGET /api/v1/user\nGET /api/v1/user/emails\nGET /api/v1/user/orgs\n```\n\nEach request returns:\n\n```http\n403 Forbidden\n```\n\n3. Send the same token to the OIDC userinfo endpoint:\n\n```http\nGET /login/oauth/userinfo\nAuthorization: Bearer \u003cread-misc-token\u003e\n```\n\n4. Observe that the request succeeds and returns identity claims, for example:\n\n```json\n{\n  \"email\": \"user@example.com\",\n  \"groups\": [\n    ...\n  ]\n}\n```\n\n### Impact\n\nHolders of narrowly scoped API tokens can obtain identity information through the OIDC userinfo endpoint regardless of the scopes assigned to the token.\n\nThe issue does not provide access to repositories, issues, pull requests, administrative functionality, or data belonging to other users.\n\nImpact is limited to disclosure of identity information associated with the authenticated user. However, it weakens the authorization boundary established by API token scopes because identity claims remain accessible even when the token lacks user- or organization-related scopes.",
  "id": "GHSA-mg4f-x9v4-6h2p",
  "modified": "2026-07-21T20:42:05Z",
  "published": "2026-07-21T20:42:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-mg4f-x9v4-6h2p"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/go-gitea/gitea"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/releases/tag/v1.27.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Gitea: OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes"
}

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-2026-55982 (GCVE-0-2026-55982)

GHSA-MG4F-X9V4-6H2P

Summary

Details

PoC

PoC Details

Reproduction Steps

Impact

Tags

Sightings

Nomenclature