CVE-2023-53667 is a medium-severity vulnerability found in the Linux kernel, specifically affecting the handling of dwNtbOutMaxSize values. The vulnerability was published on October 7, 2025, and has been analyzed thoroughly. The CVSS score for this vulnerability is 5.5, indicating a medium level of risk due to its potential impact on system availability.
This vulnerability allows for a scenario where low values of dwNtbOutMaxSize lead to improper memory allocation during the handling of CDC data. If certain conditions are met, this can result in a kernel panic, disrupting services and potentially leading to a denial of service.
Organizations should prioritize patching immediately to mitigate the risks associated with this vulnerability. The urgency stems from the fact that exploitation could lead to significant service disruptions.
Given the nature of the vulnerability, it is crucial for organizations to review their systems and ensure that they are updated to the latest kernel versions where this flaw is addressed.
Vulnerability Details
The vulnerability described in CVE-2023-53667 affects the Linux kernel in the net: cdc_ncm subsystem. It results from insufficient validation of the dwNtbOutMaxSize parameter. If this parameter is set to a value lower than the minimum allowed, the kernel's logic may allocate insufficient memory for the handling of CDC data, leading to a potential system panic.
The CVSS vector for this vulnerability is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. This indicates that the attack vector is local, the complexity is low, and it requires low privileges to exploit. The impact on availability is classified as high, while confidentiality and integrity impacts are none.
The vulnerability is classified under CWE-476, which pertains to NULL Pointer Dereference. The affected versions of the Linux kernel range from 3.16 to various versions up to 6.4 rc3, as detailed in the configurations section.
Technical Analysis
The root cause of CVE-2023-53667 lies in the handling of the dwNtbOutMaxSize parameter within the cdc_ncm subsystem of the Linux kernel. During the execution of cdc_ncm_check_tx_max(), if dwNtbOutMaxSize is set to a value lower than the calculated minimum but greater than zero, the kernel sets the transmission maximum (tx_max) to this potentially inadequate value.
The attack vector is local, meaning that an attacker would need local access to the system to exploit this vulnerability. The attack complexity is low, indicating that no significant skill is required to exploit the flaw. The privileges required for exploitation are also low, allowing an unprivileged user to trigger the vulnerability.
User interaction is not required for the exploitation of this vulnerability. If exploited, the availability impact is classified as high, leading to potential denial of service conditions, which could severely disrupt system operations.
Risk & Impact Analysis
Risk to organizations includes significant service disruptions due to the kernel panic that can occur when dwNtbOutMaxSize is inadequately validated. The blast radius potential is particularly concerning for organizations relying on the Linux kernel for critical services. With a CVSS score of 5.5, organizations should assess their systems for vulnerability and prioritize remediation efforts.
The urgency of this vulnerability is categorized as medium, indicating that while immediate action is not necessary, organizations should address it within their regular patch cycle. Monitoring for unusual system behavior and ensuring all systems are updated can mitigate risks associated with this vulnerability.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of the Linux kernel include all versions from 3.16 up to, but not including, 4.14.317, as well as various ranges up to 6.4 rc3. Organizations are advised to check their kernel versions against the provided CPE criteria to identify if they are affected.
Mitigation & Remediation
To remediate CVE-2023-53667, organizations should apply the latest patches available for their Linux kernel. Ensuring that the kernel version is updated to one that addresses this vulnerability is critical. For those unable to patch immediately, implementing configuration hardening and network controls can help mitigate the risk.
Organizations can also consider conducting regular security assessments to identify potential vulnerabilities in their systems. For more information on effective security measures, refer to the comprehensive guide on penetration testing and its role in vulnerability management.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor their systems for unusual kernel behavior and log indicators that may suggest a kernel panic. Additionally, behavioral anomalies in network traffic related to CDC data could also indicate attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2023-53667 reflects ongoing challenges in kernel development, where low-level memory management can lead to critical failures. Security teams should recognize this vulnerability as a pattern representing the importance of robust input validation.
One strategic takeaway is that regular updates and security assessments are essential for maintaining system integrity. For more information on vulnerability management, refer to our blog on vulnerability management programs and the role they play in preventing such vulnerabilities.
Moreover, organizations can benefit from understanding the nuances of security testing methodologies by exploring our guide on penetration testing methodology to enhance their security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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