GHSA-g46h-2rq9-gw5m BIT-openbao-2025-59043 CVE-2025-59043 GO-2025-4039
OpenBao has potential Denial of Service vulnerability when processing malicious unauthenticated JSON requests
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.69%
- Chance of exploitation in the next 30 days. Higher than 52.73% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
2.4.1- Upgrade github.com/openbao/openbao to this version or later
Description
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.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/openbao/openbao | < 2.4.1 |
2.4.1 |
| github.com/openbao/openbao | all versions |
No fix yet |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/openbao/openbao Go → 2.4.1
- go
go get github.com/openbao/openbao@v2.4.1 && go mod tidy
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Packages
Other links
- github.com/openbao/openbao/security/advisories/GHSA-g46h-2rq9-gw5m
- github.com/openbao/openbao/pull/1756
- github.com/openbao/openbao/commit/d418f238bc99adc72c73109faf574cc2b672880c
- discuss.hashicorp.com/t/hcsec-2025-24-vault-denial-of-service-though-complex-json-payloads…
- github.com/openbao/openbao/blob/788536bd3e10818a7b4fb00aac6affc23388e5a9/http/l…
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-xp3c-3jw3-4vcr OpenBao Skips Stricter Deny Policy for LIST operations | Medium | Also affects github.com/openbao/openbao |
| GHSA-34fc-gh42-pj53 OpenBao's Recovery Mode Vulnerable To Token Leakage via Timing Attack | Critical | Also affects github.com/openbao/openbao |
| GHSA-444v-8vxr-p36h OpenBao Agent Writes Secrets to Stdout | Low | Also affects github.com/openbao/openbao |
| GHSA-59w7-v8rr-pr4p OpenBao's Templated Policies Allow Privilege Escalation via Wildcard Characters | High | Also affects github.com/openbao/openbao |
| GHSA-8w8f-r2xv-4q4j OpenBao: Transit secrets engine crashes on key creation with `derived: true` for asymmetric key types | Medium | Also affects github.com/openbao/openbao |
| GHSA-mwr2-wmgp-crj6 OpenBao's System Backend allows Unauthorized Management of the containing Namespace | Low | Also affects github.com/openbao/openbao |
| GHSA-c36x-h252-g9x2 OpenBao: Cross-namespace lease revocation/renewal via canonical sys/leases/{revoke,renew} — incomplete fix of CVE-2026-45808 | Low | Also affects github.com/openbao/openbao |
| GHSA-6mwx-4547-5vc9 OpenBao: LDAPi ldaputil (wrong escape func) | Medium | Also affects github.com/openbao/openbao |
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