CVE-2026-26247 (GCVE-0-2026-26247)

Vulnerability from cvelistv5 – Published: 2026-07-03 20:19 – Updated: 2026-07-03 20:19
VLAI
Title
Gitea OAuth2 PKCE S256 challenges are not enforced during token exchange
Summary
Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check.
Severity
No CVSS data available.
CWE
Assigner
References
Impacted products
Vendor Product Version
Gitea Gitea Open Source Git Server Affected: 0 , < 1.25.5 (semver)
Create a notification for this product.
Credits
Aisle Research
Show details on NVD website
To clipboard 

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      "credits": [
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          "lang": "en",
          "type": "reporter",
          "value": "Aisle Research"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-03T20:19:34.820Z",
        "orgId": "88ee5874-cf24-4952-aea0-31affedb7ff2",
        "shortName": "Gitea"
      },
      "references": [
        {
          "name": "GitHub Pull Request #36462",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/go-gitea/gitea/pull/36462"
        },
        {
          "name": "GitHub Pull Request #36477",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/go-gitea/gitea/pull/36477"
        },
        {
          "name": "Gitea v1.25.5 Release",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/go-gitea/gitea/releases/tag/v1.25.5"
        },
        {
          "name": "Gitea v1.25.5 Release Blog Post",
          "tags": [
            "release-notes"
          ],
          "url": "https://blog.gitea.com/release-of-1.25.5/"
        }
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      "title": "Gitea OAuth2 PKCE S256 challenges are not enforced during token exchange",
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    "datePublished": "2026-07-03T20:19:34.820Z",
    "dateReserved": "2026-03-03T03:25:28.654Z",
    "dateUpdated": "2026-07-03T20:19:34.820Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-07-04",
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      "percentile": "0.06155"
    },
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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