OpenBao's Certificate Authentication Allows Token Renewal With Different Certificate
Low3.1CVE-2026-39388 · Published Apr 21, 2026 · updated Sep 10, 2026
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| github.com/openbao/openbao Go | < 0.0.0-20260420160924-abe84e1af4c3 | 0.0.0-20260420160924-abe84e1af4c3 |
Details and references
### 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.
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|---|---|---|---|
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| Apr 21 | OpenBao's Token Store Allows Cross-Namespace Renewal, Revocation CVE-2026-40264Lowfixed in 0.0.0-20260420162526-f58111d2ca54 | Low | 0.0.0-20260420162526-f58111d2ca54 |
| May 5 | OpenBao's Namespace Deletion May Not Delete Data Properly CVE-2026-42186Lowfixed in 0.0.0-20260420173541-6d2e0506e2b4 | Low | 0.0.0-20260420173541-6d2e0506e2b4 |
| Mar 26 | OpenBao has Reflected XSS in its OIDC authentication error message CVE-2026-33758Criticalfixed in 0.0.0-20260325133417-6e2b2dd84f0e | Critical | 0.0.0-20260325133417-6e2b2dd84f0e |
| Mar 26 | OpenBao lacks user confirmation for OIDC direct callback mode CVE-2026-33757Critical9.6fixed in 0.0.0-20260325142553-e32103951925 | Critical9.6 | 0.0.0-20260325142553-e32103951925 |