Security Bulletin
Summary
Vault's PKI secrets engine ACME server did not restrict certificate identities that ACME challenges do not validate when issuing certificates under the default directory policy. This may allow an ACME client to obtain a certificate containing unverified identity claims, potentially enabling impersonation toward systems that trust certificates issued by the affected Vault PKI mount. This vulnerability (CVE-2026-105818) is fixed in Vault Community Edition 2.1.2, and Vault Enterprise 2.1.2, 1.21.12, 1.20.17, and 1.19.23.
Vulnerability Details
CVEID: CVE-2026-105818
DESCRIPTION: When the default_directory_policy was set to sign-verbatim (the default, which also applies if the setting is not configured), Vault could include subject alternative name types other than DNS names and IP addresses from the certificate signing request in the issued certificate, even though these identities are never verified by ACME challenges. An ACME client that completes validation for an identifier it controls could therefore obtain a certificate that also asserts other identities. This issue only affects PKI mounts with ACME enabled and using the sign-verbatim default directory policy, either explicitly or by default. Mounts that disable the default directory or set it to a role that constrains these subject alternative name types are not affected. Where external account binding is required, exploitation is limited to clients holding a valid binding.
CWE: CWE-345: Insufficient Verification of Data Authenticity
CVSS Source: HashiCorp Inc.
CVSS Base score: 5.9
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| Vault Community Edition | affected from 1.14.0 up to 2.1.2 |
| Vault Enterprise | affected from 1.14.0 up to 2.1.2, unaffected from 1.21.12, 1.20.17, 1.19.23 |
Remediation/Fixes
Customers should evaluate the risk associated with this issue and consider upgrading to Vault Community Edition 2.1.2, or Vault Enterprise 2.1.2, 1.21.12, 1.20.17, or 1.19.23. After upgrading, the sign-verbatim policy rejects certificate requests containing these unverified subject alternative name types. Operators who require the previous behavior can opt in with the new sign-verbatim-unsafe policy, accepting that issued certificates may contain unverified identity claims. Until upgrading, configuring the default directory policy to use a role that restricts these subject alternative name types, or disabling the default directory, mitigates this issue.
Get Notified about Future Security Bulletins
References
Acknowledgement
This issue was identified by an external party.
Change History
07 Oct 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
Was this topic helpful?
Document Information
Modified date:
07 October 2026
Initial Publish date:
07 October 2026
UID
ibm17291622