GHSA-6HG9-M8FV-WQ83

Vulnerability from github – Published: 2026-04-22 00:31 – Updated: 2026-04-22 00:31
VLAI?
Details

An improper neutralization of special elements vulnerability was identified in GitHub Enterprise Server that allowed an authenticated Management Console administrator to execute arbitrary OS commands via shell metacharacter injection in proxy configuration fields such as http_proxy. Exploitation of this vulnerability required access to the GitHub Enterprise Server instance and administrator privileges to the Management Console. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.

Severity ?
8.1 (High)
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
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{
  "affected": [],
  "aliases": [
    "CVE-2026-4821"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-21T23:16:22Z",
    "severity": "HIGH"
  },
  "details": "An improper neutralization of special elements vulnerability was identified in GitHub Enterprise Server that allowed an authenticated Management Console administrator\u00a0to execute arbitrary OS commands\u00a0via\u00a0shell metacharacter injection in proxy configuration fields such as\u00a0http_proxy.\u00a0Exploitation of this vulnerability required access to the GitHub Enterprise Server instance and administrator privileges to the Management Console. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.",
  "id": "GHSA-6hg9-m8fv-wq83",
  "modified": "2026-04-22T00:31:41Z",
  "published": "2026-04-22T00:31:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4821"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.24"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5"
    },
    {
      "type": "WEB",
      "url": "https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/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",
      "type": "CVSS_V4"
    }
  ]
}


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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.