CVE-2026-120263 (GCVE-0-2026-120263)

Vulnerability from cvelistv5 – Published: 2026-11-01 09:47 – Updated: 2026-11-01 09:47
VLAI
Title
Gitea OAuth2 account auto-linking takeover through the sign-up form
Summary
When `[oauth2_client].ACCOUNT_LINKING` is set to `auto` (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user's name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider's email or provider-derived user name; otherwise the account password is required.
Severity
No CVSS data available.
CWE
  • CWE-287 - Improper Authentication
  • CWE-639 - Authorization Bypass Through User-Controlled Key
Assigner
Gitea CNA under the mitre root
CNA scorecard C 61/100 over 185 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Gitea Gitea Affected: 0 , < 28.3.0 (semver)
guessed Create a notification for this product.
Credits
https://github.com/adrian-doyensec https://github.com/AdamKorcz https://github.com/DshtAnger https://github.com/ivantsepp https://github.com/bircni
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageName": "gitea.dev",
          "product": "Gitea",
          "vendor": "Gitea",
          "versions": [
            {
              "lessThan": "28.3.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "https://github.com/adrian-doyensec"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "https://github.com/AdamKorcz"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "https://github.com/DshtAnger"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "https://github.com/ivantsepp"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "https://github.com/bircni"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "When `[oauth2_client].ACCOUNT_LINKING` is set to `auto` (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user\u0027s name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider\u0027s email or provider-derived user name; otherwise the account password is required."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287: Improper Authentication",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-639",
              "description": "CWE-639: Authorization Bypass Through User-Controlled Key",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-01T09:47:09.191Z",
        "orgId": "88ee5874-cf24-4952-aea0-31affedb7ff2",
        "shortName": "Gitea"
      },
      "references": [
        {
          "name": "GitHub Security Advisory GHSA-8p3x-w464-4g6v",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-8p3x-w464-4g6v"
        },
        {
          "name": "Fix: go-gitea/gitea pull request #40121",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/go-gitea/gitea/pull/40121"
        },
        {
          "name": "Fix backport to release/v28: go-gitea/gitea pull request #40137",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/go-gitea/gitea/pull/40137"
        },
        {
          "name": "Gitea 28.3.0 release announcement",
          "tags": [
            "release-notes"
          ],
          "url": "https://blog.gitea.com/release-of-28.3.0/"
        },
        {
          "name": "go-gitea/gitea v28.3.0 release",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/go-gitea/gitea/releases/tag/v28.3.0"
        }
      ],
      "title": "Gitea OAuth2 account auto-linking takeover through the sign-up form"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "88ee5874-cf24-4952-aea0-31affedb7ff2",
    "assignerShortName": "Gitea",
    "cveId": "CVE-2026-120263",
    "datePublished": "2026-11-01T09:47:09.191Z",
    "dateReserved": "2026-11-01T08:48:41.149Z",
    "dateUpdated": "2026-11-01T09:47:09.191Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-120263",
      "date": "2026-11-01",
      "epss": "0.00198",
      "percentile": "0.09603"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "packageName": "gitea.dev",
                "product": "Gitea",
                "vendor": "Gitea",
                "versions": [
                  {
                    "lessThan": "28.3.0",
                    "status": "affected",
                    "version": "0",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "When `[oauth2_client].ACCOUNT_LINKING` is set to `auto` (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user\u0027s name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider\u0027s email or provider-derived user name; otherwise the account password is required."
          }
        ],
        "id": "CVE-2026-120263",
        "lastModified": "2026-11-01T10:18:37.637",
        "metrics": {},
        "published": "2026-11-01T10:18:37.520",
        "references": [
          {
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "url": "https://blog.gitea.com/release-of-28.3.0/"
          },
          {
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "url": "https://github.com/go-gitea/gitea/pull/40121"
          },
          {
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "url": "https://github.com/go-gitea/gitea/pull/40137"
          },
          {
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "url": "https://github.com/go-gitea/gitea/releases/tag/v28.3.0"
          },
          {
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-8p3x-w464-4g6v"
          }
        ],
        "sourceIdentifier": "88ee5874-cf24-4952-aea0-31affedb7ff2",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-287"
              },
              {
                "lang": "en",
                "value": "CWE-639"
              }
            ],
            "source": "88ee5874-cf24-4952-aea0-31affedb7ff2",
            "type": "Secondary"
          }
        ]
      }
    }
  }
}



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