OpenBao has potential Denial of Service vulnerability when processing malicious unauthenticated JSON requests

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2025-59043: 0.69% estimated exploitation activity in the next 30 days; percentile 52.75 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 [maxrequestsize (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…

Published by the source

17 Oct 2025, 17:08 UTC

Last modified by the source

17 Oct 2025, 19:07 UTC

Source last checked

26 Oct 2026, 15:13 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g46h-2rq9-gw5m

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# Patch Next advisory brief: CVE-2025-59043

Advisory: OpenBao has potential Denial of Service vulnerability when processing malicious unauthenticated JSON requests
IDs: CVE-2025-59043, GHSA-g46h-2rq9-gw5m
Record: https://patchnext.com/advisories/cve-2025-59043 (revision 1, source checked 26 Oct 2026, 15:13 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/openbao/openbao 2.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/openbao/openbao: affected <= 2.4.0; fixed in 2.4.1

## Suggested inspection (read-only)
- Go github.com/openbao/openbao: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/openbao/openbao.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-g46h-2rq9-gw5m (GitHub-reviewed advisory GHSA-g46h-2rq9-gw5m lists affected ranges: Go github.com/openbao/openbao >=0 <=2.4.0)

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