CVE-2025-59043 OpenBao vulnerable to denial of service via malicious JSON request processing
Unauthenticated attackers can cause out-of-memory crashes in OpenBao by sending crafted JSON payloads that bypass size limits.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-59043?
CVE-2025-59043 is a high-severity denial of service vulnerability in openbao, published on 17 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-400
Which versions are affected by CVE-2025-59043?
4 open source packages ship an affected version, including github.com/openbao/openbao and openbao. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/openbao/openbao Go | All versions | None |
github.com/openbao/openbao Go | All versions | 2.4.1 |
github.com/openbao/openbao Go | All versions | 2.4.1 |
openbao Bitnami | All versions | 2.4.1 |
Products include Openbao Openbao.
How do I fix CVE-2025-59043?
Upgrade github.com/openbao/openbao to 2.4.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-59043 being exploited?
There is no known exploitation of CVE-2025-59043 in the wild and no public exploit code.
Other vulnerabilities in openbao
- CVE-2026-33757 OpenBao lacks user confirmation for OIDC direct callback mode
- CVE-2026-33758 OpenBao has Reflected XSS in its OIDC authentication error message
- CVE-2025-54997 OpenBao: Privileged Operator May Execute Code on the Underlying Host
- CVE-2025-64761 OpenBao Privileged Operator Identity Group Root Escalation
- CVE-2025-54996 OpenBao Root Namespace Operator May Elevate Token Privileges
Sources
Also known as BIT-openbao-2025-59043, GHSA-g46h-2rq9-gw5m, GO-2025-4039.