CVE-2026-39388: Github.com/openbao/openbao OpenBao's Certificate Authentication Allows Token Vulnerability
LOWCVE-2026-39388 is a LOW (CVSS 3.1) openbao's certificate authentication allows token vulnerability (CWE-295: Improper Certificate Validation) affecting Github.com/openbao/openbao libraries in the Go ecosystem. The issue involves openbao's certificate authentication allows token renewal with different certificate. Remediation is available by upgrading affected packages to version 0.0.0-20260420160924-abe84e1af4c3.
CVE-2026-39388 at a Glance
Security Impact
CVSS: 3.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N).
How to Fix CVE-2026-39388
To remediate this vulnerability, upgrade all affected Github.com/openbao/openbao dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/openbao/openbao to 0.0.0-20260420160924-abe84e1af4c3Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/openbao/openbaoHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-39388, inspect your project dependencies for Github.com/openbao/openbao:
inspect dependencies for github.com/openbao/openbaoAnalyze the terminal output to locate any version of Github.com/openbao/openbao in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.0.0-20260420160924-abe84e1af4c3), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-295: Improper Certificate Validation, where the product does not validate, or incorrectly validates, a certificate. In Github.com/openbao/openbao, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-39388 Affected Github.com/openbao/openbao Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/openbao/openbao
|
Go |
< 0.0.0-20260420160924-abe84e1af4c3
|
0.0.0-20260420160924-abe84e1af4c3
|
References
Frequently Asked Questions
What is CVE-2026-39388?
Which Github.com/openbao/openbao versions are affected?
What version fixes CVE-2026-39388?
Is github.com/openbao/openbao affected?
What is the CVSS score of CVE-2026-39388?
What CWE is associated with CVE-2026-39388?
How can I check Go dependencies for CVE-2026-39388?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-7ccv-rp6m-rffr",
"modified" : "2026-04-27T16:35:57Z",
"published" : "2026-04-21T17:26:42Z",
"aliases" : [ "CVE-2026-39388" ],
"summary" : "OpenBao's Certificate Authentication Allows Token Renewal With Different Certificate",
"details" : "### Background\n\nOpenBao's Certificate authentication method, when a token renewal is requested and `disable_binding=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.\n\n### Impact\n\nDue 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. \n\nThis vulnerability is originally from HashiCorp Vault.\n\n### Patches\n\nThis has been addressed in v2.5.3.\n\n### Workarounds\n\nEnsure privileged roles are tightly scoped to single certificates.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N"
}, {
"type" : "CVSS_V4",
"score" : "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"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/openbao/openbao"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.0.0-20260420160924-abe84e1af4c3"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/openbao/openbao/security/advisories/GHSA-7ccv-rp6m-rffr"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39388"
}, {
"type" : "WEB",
"url" : "https://github.com/openbao/openbao/pull/2932"
}, {
"type" : "WEB",
"url" : "https://github.com/openbao/openbao/commit/9ab7a066826cc544c30e8b203f8f472076f366e1"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/openbao/openbao"
}, {
"type" : "WEB",
"url" : "https://github.com/openbao/openbao/releases/tag/v2.5.3"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-295", "CWE-863" ],
"severity" : "LOW",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-21T17:26:42Z",
"nvd_published_at" : "2026-04-21T01:16:06Z"
}
}