Affected: Bitnami: openbao

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.

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.

Affected: Go: github.com/openbao/openbao

### 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 a…

govulncheck-vulndb-0.0.20251105T184115-1.1 on GA media

Ein Angreifer kann mehrere Schwachstellen in OpenBao ausnutzen, um Informationen offenzulegen, und um einen Denial of Service Angriff durchzuführen.