Issue Summary: An error in the callback used to verify the certificate
provided in a Root CA key update Certificate Management Protocol (CMP)
message response rendered the certificate validation ineffectual, which
could lead to escalation of credentials from the Registration Authority (RA)
level to the root Certification Authority (root CA) level.

Impact Summary: The Registration Autority could replace the root CA
certificate for the CMP clients with an arbitrary root CA certificate.

One of the parts of the Certificate Management Protocol (CMP), specified in
RFC 9810, is Root Certification Authority (root CA) key Rollover,
which is sent by the server in a message with type 'id-it-rootCaKeyUpdate'.
As part of these messages, 'newWithOld' certificate, the new root CA
certificate signed with the old root CA key, is provided, and verifying its
signature is crucial for transferring the trust from the old CA key to the
new one.

The 'id-it-rootCaKeyUpdate' messages are expected to be processed with
OSSL_CMP_get1_rootCaKeyUpdate(), that is expected to verify the 'newWithOld'
certificate. A typo in the certificate chain building code led to adding
an incorrect certificate ('newWithOld' instead of 'oldRoot') to the
certificate chain, rendering the certificate verification process ineffectual
(only the issuer name and the algorithm OIDs were verified by other parts
of the verification code).

An attacker who already has credentials that satisfy the CMP message
protection checks can generate a new key pair and use a crafted self-signed
certificate in its 'id-it-rootCaKeyUpdate' CMP messages which affected CMP
clients would accept as a new trust anchor.

Significant preconditions for the attack (having valid RA-level credentials)
are the reason the issue was assigned Low severity.

The FIPS modules are not affected by this issue, as the affected code is
outside the OpenSSL FIPS module boundary.

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Source ID Title
Ubuntu USN Ubuntu USN USN-8414-1 OpenSSL vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 09 Jun 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 09 Jun 2026 18:00:00 +0000

Type Values Removed Values Added
First Time appeared Openssl
Openssl openssl
Vendors & Products Openssl
Openssl openssl

Tue, 09 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Description Issue Summary: An error in the callback used to verify the certificate provided in a Root CA key update Certificate Management Protocol (CMP) message response rendered the certificate validation ineffectual, which could lead to escalation of credentials from the Registration Authority (RA) level to the root Certification Authority (root CA) level. Impact Summary: The Registration Autority could replace the root CA certificate for the CMP clients with an arbitrary root CA certificate. One of the parts of the Certificate Management Protocol (CMP), specified in RFC 9810, is Root Certification Authority (root CA) key Rollover, which is sent by the server in a message with type 'id-it-rootCaKeyUpdate'. As part of these messages, 'newWithOld' certificate, the new root CA certificate signed with the old root CA key, is provided, and verifying its signature is crucial for transferring the trust from the old CA key to the new one. The 'id-it-rootCaKeyUpdate' messages are expected to be processed with OSSL_CMP_get1_rootCaKeyUpdate(), that is expected to verify the 'newWithOld' certificate. A typo in the certificate chain building code led to adding an incorrect certificate ('newWithOld' instead of 'oldRoot') to the certificate chain, rendering the certificate verification process ineffectual (only the issuer name and the algorithm OIDs were verified by other parts of the verification code). An attacker who already has credentials that satisfy the CMP message protection checks can generate a new key pair and use a crafted self-signed certificate in its 'id-it-rootCaKeyUpdate' CMP messages which affected CMP clients would accept as a new trust anchor. Significant preconditions for the attack (having valid RA-level credentials) are the reason the issue was assigned Low severity. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
Title Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate
Weaknesses CWE-295
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published:

Updated: 2026-06-09T19:38:05.632Z

Reserved: 2026-04-29T09:22:27.969Z

Link: CVE-2026-42769

cve-icon Vulnrichment

Updated: 2026-06-09T19:37:50.572Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-06-09T17:17:08.377

Modified: 2026-06-09T19:38:32.463

Link: CVE-2026-42769

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-09T19:00:15Z

Weaknesses