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Issue summary: An attacker-controlled CMP (Certificate...

Moderate severity Unreviewed Published Jun 9, 2026 to the GitHub Advisory Database • Updated Jun 10, 2026

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

Issue summary: An attacker-controlled CMP (Certificate Management Protocol)
server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the
application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could
craft a CMP response containing a CRMF (Certificate Request Message Format)
CertRepMessage with an EncryptedValue structure where the symmAlg field
has an algorithm OID but no parameters field. When the OpenSSL CMP client
processes this response, the NULL dereference occurs, causing a crash of
the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary.

References

Published by the National Vulnerability Database Jun 9, 2026
Published to the GitHub Advisory Database Jun 9, 2026
Last updated Jun 10, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(19th percentile)

Weaknesses

NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL. Learn more on MITRE.

CVE ID

CVE-2026-42767

GHSA ID

GHSA-gxhg-7jx8-m22j

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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