GHSA-7ccv-rp6m-rffr BIT-openbao-2026-39388 CVE-2026-39388 GO-2026-5213
OpenBao's Certificate Authentication Allows Token Renewal With Different Certificate
- Severity
- 0.0 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.10%
- Chance of exploitation in the next 30 days. Higher than 0.89% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
0.0.0-20260420160924-abe84e1af4c3- Upgrade github.com/openbao/openbao to this version or later
Description
Background
OpenBao'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.
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 roles are tightly scoped to single certificates.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/openbao/openbao | < 0.0.0-20260420160924-abe84e1af4c3 |
0.0.0-20260420160924-abe84e1af4c3 |
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 → 0.0.0-20260420160924-abe84e1af4c3
- go
go get github.com/openbao/openbao@v0.0.0-20260420160924-abe84e1af4c3 && go mod tidy
Severity breakdown
CVSS 4.0 0.0
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
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- Present
- Privileges required
- High
- User interaction
- Passive
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 3.1
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- High
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-295: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How to prevent it
- Architecture and Design, Implementation: Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- Implementation: If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Packages
Other links
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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