OpenBao's Certificate Authentication Allows Token Renewal With Different Certificate

Exploitation

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

CVSS 4.0

2.0 · CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-39388: 0.10% estimated exploitation activity in the next 30 days; percentile 0.90 (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.

Background OpenBao's Certificate authentication method, when a token renewal is requested and disablebinding=true is set, attempts to verify the current request's presented mTLS certificate matches the original. Token renewals for other authentication methods do not require any supplied login information. Impact Due to incorrect matching, the certificate authentication method would allow renewal of tokens for which the attacker had a sibling certificate+key signed by the same CA, but which did not necessarily match the original role or the originally supplied certificate. This implies an attacker could still authenticate to OpenBao in a similar scope, however, token renewal implies that an attacker may be able to extend the lifetime of dynamic leases held by the original token. This attack requires knowledge of either the original token or its accessor. This vulnerability is originally from HashiCorp Vault. Patches This has been addressed in v2.5.3. Workarounds Ensure privileged…

Published by the source

21 Apr 2026, 17:26 UTC

Last modified by the source

27 Apr 2026, 16:36 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7ccv-rp6m-rffr

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# Patch Next advisory brief: CVE-2026-39388

Advisory: OpenBao's Certificate Authentication Allows Token Renewal With Different Certificate
IDs: CVE-2026-39388, GHSA-7ccv-rp6m-rffr
Record: https://patchnext.com/advisories/cve-2026-39388 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.0)
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 0.0.0-20260420160924-abe84e1af4c3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/openbao/openbao: affected < 0.0.0-20260420160924-abe84e1af4c3; fixed in 0.0.0-20260420160924-abe84e1af4c3

## 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-7ccv-rp6m-rffr (GitHub-reviewed advisory GHSA-7ccv-rp6m-rffr lists affected ranges: Go github.com/openbao/openbao >=0 <0.0.0-20260420160924-abe84e1af4c3)

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