FKIE_CVE-2026-1999

Vulnerability from fkie_nvd - Published: 2026-02-18 21:16 - Updated: 2026-02-19 22:07
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Summary
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program.
References
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.11Product, Release Notes
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.5Product, Release Notes
product-cna@github.comhttps://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.2Product, Release Notes
Impacted products
Vendor Product Version
github enterprise_server *
github enterprise_server *
github enterprise_server *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
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              "versionEndExcluding": "3.17.11",
              "vulnerable": true
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          "negate": false,
          "operator": "OR"
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de autorizaci\u00f3n incorrecta fue identificada en GitHub Enterprise Server que permit\u00eda a un atacante fusionar su propia solicitud de extracci\u00f3n en un repositorio sin tener acceso de env\u00edo al explotar una omisi\u00f3n de autorizaci\u00f3n en la mutaci\u00f3n enable_auto_merge para solicitudes de extracci\u00f3n. Este problema solo afect\u00f3 a los repositorios que permiten la bifurcaci\u00f3n, ya que el ataque se basa en abrir una solicitud de extracci\u00f3n desde una bifurcaci\u00f3n controlada por el atacante en el repositorio objetivo. La explotaci\u00f3n solo fue posible en escenarios espec\u00edficos. Requer\u00eda un estado de solicitud de extracci\u00f3n limpio y solo se aplicaba a ramas sin reglas de protecci\u00f3n de rama habilitadas. Esta vulnerabilidad afect\u00f3 a las versiones de GitHub Enterprise Server anteriores a 3.19.2, 3.18.5 y 3.17.11, y fue corregida en las versiones 3.19.2, 3.18.5 y 3.17.11. Esta vulnerabilidad fue reportada a trav\u00e9s del programa GitHub Bug Bounty."
    }
  ],
  "id": "CVE-2026-1999",
  "lastModified": "2026-02-19T22:07:05.300",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "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",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "LOW",
          "subIntegrityImpact": "HIGH",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
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        "source": "product-cna@github.com",
        "type": "Secondary"
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  },
  "published": "2026-02-18T21:16:24.147",
  "references": [
    {
      "source": "product-cna@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.11"
    },
    {
      "source": "product-cna@github.com",
      "tags": [
        "Product",
        "Release Notes"
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    },
    {
      "source": "product-cna@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
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    }
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  "sourceIdentifier": "product-cna@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "product-cna@github.com",
      "type": "Secondary"
    }
  ]
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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Detection rules are retrieved from Rulezet.