ghsa-46g3-37rh-v698

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "<= 2.15.1",
        "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-46g3-37rh-v698/GHSA-46g3-37rh-v698.json"
      },
      "package": {
        "ecosystem": "GitHub Actions",
        "name": "step-security/harden-runner"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.16.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32947"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-693",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-17T18:38:16Z",
    "nvd_published_at": "2026-03-20T05:16:13Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nA vulnerability exists in the Community Tier of Harden-Runner that allows bypassing the `egress-policy: block` network restriction using DNS over HTTPS (DoH).\n\nHarden-Runner secures GitHub Actions workflows on runners by applying network policies, including an `allowed-endpoints` configuration that limits outbound traffic to specified domains and ports (e.g., `github.com:443`). In `egress-policy: block` mode, non-compliant connections are intercepted and denied. \n\nThis vulnerability exploits DoH, a protocol that encapsulates DNS queries within HTTPS requests. By crafting a DNS query that embeds exfiltrated data as a subdomain (e.g., encoding the runner's hostname into a label), an attacker can route the request through a permitted HTTPS endpoint like `dns.google` (`8.8.8.8`'s DoH service). The resolver processes the query and forwards it to the attacker's controlled domain, achieving exfiltration without directly accessing the blocked destination. This evades Harden-Runner's domain-based filtering, as the initial HTTPS connection appears legitimate. \n\nThis vulnerability requires the attacker to already have code execution capabilities within the GitHub Actions workflow.\n\nThe Enterprise Tier of Harden-Runner is **not affected** by this vulnerability.\n\n## Impact\n\nWhen Harden-Runner is configured with `egress-policy: block` and a restrictive `allowed-endpoints` list, an attacker with existing code execution capabilities within a GitHub Actions workflow can bypass the allowed domains check via DNS over HTTPS by proxying DNS queries through a permitted resolver (e.g., Google's DoH service). This allows data exfiltration even when `allowed-endpoints` is set to only whitelisted domains.\n\nThis vulnerability affects only the Community Tier. It requires the attacker to already have code execution capabilities within the GitHub Actions workflow.\n\n## Remediation\n\n### For Community Tier Users\n\nUpgrade to Harden-Runner v2.16.0 or later. \n\n### For Enterprise Tier Users\n\nNo action required. Enterprise tier customers are not affected by this vulnerability.\n\n## Credit \n\nWe would like to thank [Devansh Batham](https://github.com/devanshbatham) for responsibly disclosing this vulnerability through our security reporting process.",
  "id": "GHSA-46g3-37rh-v698",
  "modified": "2026-03-20T21:34:59.431085Z",
  "published": "2026-03-17T18:38:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/step-security/harden-runner/security/advisories/GHSA-46g3-37rh-v698"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32947"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/step-security/harden-runner"
    },
    {
      "type": "WEB",
      "url": "https://github.com/step-security/harden-runner/releases/tag/v2.16.0"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)"
}