CVE-2026-42767
Description
A flaw was found in OpenSSL. An attacker controlling a Certificate Management Protocol (CMP) server, or acting as a man-in-the-middle, could craft a malicious CMP response. This response, containing a Certificate Request Message Format (CRMF) CertRepMessage with a specific malformed EncryptedValue structure, would trigger a NULL pointer dereference in the OpenSSL CMP client. This vulnerability leads to a crash of the application, resulting in a Denial of Service (DoS).
Statement
This is a Low severity issue. A null pointer dereference flaw in the OpenSSL Certificate Management Protocol (CMP) client could be triggered by an attacker-controlled CMP server. This could lead to a denial of service in applications that process untrusted CMP/CRMF messages.
Mitigation
To mitigate this issue, ensure that OpenSSL CMP client applications only communicate with trusted Certificate Management Protocol (CMP) servers. If CMP client functionality is not required, consider disabling or restricting its use to reduce exposure.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 5.9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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