CVE-2026-63073
Description
A flaw was found in OpenSSL. A malicious CMP (Certificate Management Protocol) endpoint can send an unexpected distinguished name (DN) directly as the format string argument to ERR_raise_data(), causing the application to dereference and write to unrelated stack contents. This can lead to a crash in the CMP client, resulting in a denial of service.
Statement
Applications acting as a CMP client connecting to a malicious or intercepted CMP server are vulnerable to this issue, limiting its exposure. Also, the CMP client needs to enforce an expected sender or use a pinned server certificate whose subject becomes the default expected sender. This flaw can cause the application to dereference and write to unrelated stack contents, leading to a crash in the CMP client and resulting in a denial of service. There is no controlled memory write, arbitrary-address read or path to code execution. For these reasons, this vulnerability has been rated with a low severity.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
Format string problems allow for information disclosure which can severely simplify exploitation of the program.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Format string problems can result in the execution of arbitrary code, buffer overflows, denial of service, or incorrect data representation.
Frequently Asked Questions
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