FKIE_CVE-2026-6736

Vulnerability from fkie_nvd - Published: 2026-05-07 22:16 - Updated: 2026-05-11 17:20
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Summary
An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited to the default base permissions configured on the instance. Exploitation required network access to a GHES instance configured with an external authentication provider. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, and 3.16.18.
References
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18Release Notes, Vendor Advisory
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15Release Notes, Vendor Advisory
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9Release Notes, Vendor Advisory
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6Release Notes, Vendor Advisory
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2Release Notes, Vendor Advisory
Impacted products
Vendor Product Version
github enterprise_server *
github enterprise_server *
github enterprise_server *
github enterprise_server *
github enterprise_server *
To clipboard 

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    }
  ],
  "id": "CVE-2026-6736",
  "lastModified": "2026-05-11T17:20:51.507",
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        "source": "nvd@nist.gov",
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          "Recovery": "NOT_DEFINED",
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          "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",
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          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
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          "valueDensity": "NOT_DEFINED",
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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.

Sightings

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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.
  • 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.