OpenBao vulnerable to denial of service via malicious JSON request processing

Open Source Vulnerabilities GO-2025-4039

OpenBao has potential Denial of Service vulnerability when processing malicious unauthenticated JSON requests in github.com/openbao/openbao. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/openbao/openbao before v2.4.1.

Open Source Vulnerabilities GHSA-g46h-2rq9-gw5m

### Summary JSON objects after decoding might use more memory than their serialized version. It is possible to tune a JSON to maximize the factor between serialized memory usage and deserialized memory usage (similar to a zip bomb). While reproducing the issue, we could reach a factor of about 35. This can be used to circumvent the [`max_request_size` (https://openbao.org/docs/configuration/listener/tcp/) configuration parameter, which is meant to protect against Denial of Service attacks, and also makes Denial of Service attacks easier in general, as the attacker needs much less resources. ### Details The request body is parsed into a `map[string]interface{}` https://github.com/openbao/openbao/blob/788536bd3e10818a7b4fb00aac6affc23388e5a9/http/logical.go#L50 very early in the request handling chain (before authentication), which means an attacker can send a specifically crafted JSON object and cause an OOM crash. Additionally, for simpler requests with large numbers of strings, the audit subsystem can consume large quantities of CPU. To remediate, set `max_request_json_memory` and `max_request_json_strings`. ### Impact - Unauthenticated Denial of Service ### Resources This issue was disclosed directly to HashiCorp and is the OpenBao equivalent of the following tickets: - https://discuss.hashicorp.com/t/hcsec-2025-24-vault-denial-of-service-though-complex-json-payloads/76393 - https://nvd.nist.gov/vuln/detail/CVE-2025-6203 HashiCorp attributes the problem to the audit subsystem. For OpenBao, it was noted the problem was additionally in the requests handling logic.

Open Source Vulnerabilities CVE-2025-59043

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.

Open Source Vulnerabilities BIT-openbao-2025-59043

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.