In the Linux kernel, a vulnerability has been identified related to error handling in the port selection structure. This vulnerability allows for potential kernel crashes due to the mishandling of memory during the destruction of lag definers. Specifically, if the creation of port selection structures fails, the subsequent destruction process can lead to double-destruction, causing a kernel NULL pointer dereference.
With a CVSS score of 5.5, this vulnerability is classified as medium severity. The implications of this vulnerability are significant as it can lead to system downtime and operational disruptions. The risk to organizations includes kernel crashes, which can compromise system availability.
Currently, there are no known public exploits for this vulnerability, and it has not been included in the Known Exploited Vulnerabilities (KEV) database. However, organizations should prioritize patching this vulnerability as part of their routine maintenance.
Organizations should prioritize patching immediately.
Vulnerability Details
The vulnerability described in CVE-2025-21675 stems from the Linux kernel's handling of port selection structures during error conditions. When the creation of these structures fails, the system can attempt to destroy them incorrectly, leading to a kernel crash.
The CVSS score of 5.5 indicates a medium severity, with an attack vector classified as local, meaning that an attacker must have local access to the vulnerable system to exploit this vulnerability. The availability impact is rated as high, highlighting the potential for significant disruption.
The vulnerability affects versions of the Linux kernel from 5.16 up to less than 6.1.127, as well as several release candidates of version 6.13. The internal error generated during the incident indicates a NULL pointer dereference, which could lead to a system crash.
Technical Analysis
The root cause of CVE-2025-21675 is an error in the management of port selection structures during the creation and destruction process. When the system attempts to create these structures and the operation fails, it leads to a double destruction scenario, which results in a NULL pointer dereference.
The attack vector is local, requiring an attacker to have access to the system. The complexity of the attack is low, as it does not require any special privileges or user interactions. An attacker could exploit this vulnerability without needing to authenticate, leading to a potential crash of the kernel.
The impact of this vulnerability on confidentiality and integrity is rated as none, but it poses a high risk to availability. Organizations should be aware that a successful exploitation can lead to system outages.
Risk & Impact Analysis
The real-world deployment of this vulnerability can lead to significant risks, especially for organizations relying heavily on Linux systems for critical operations. A kernel crash can result in downtime, affecting productivity and potentially leading to financial losses.
The blast radius of this vulnerability could be extensive, as the kernel is a core component of the operating system. Affected organizations must be proactive in their patch management processes to mitigate the potential impacts.
Given the CVSS score and the potential for significant availability impact, organizations should address this vulnerability in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects the Linux kernel versions starting from 5.16 and up to versions prior to 6.1.127. It also impacts versions 6.13-rc1 through 6.13-rc7.
Mitigation & Remediation
Organizations are advised to patch their systems to the latest version of the Linux kernel to mitigate this vulnerability. The patches are available in the official repositories, and administrators should ensure they apply these updates as part of their regular maintenance routine.
Penetration testing can also help identify similar vulnerabilities and ensure systems are hardened against potential exploitation.
Detection Guidance
Monitoring logs for kernel errors related to memory management and tracking system crashes can help detect attempts to exploit this vulnerability. Organizations should also review their system configurations for any unauthorized changes.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-21675 lies in its representation of potential weaknesses in the Linux kernel's error handling, which can lead to severe operational impacts. This vulnerability reflects a pattern of vulnerabilities that arise from improper memory management.
Organizations should learn from this incident and implement rigorous testing and validation processes for kernel updates to minimize the risk of similar vulnerabilities emerging in the future.
Security teams should prioritize understanding kernel-level vulnerabilities and invest in continuous security education to enhance their defensive posture.
Developing a robust vulnerability management program will ensure that organizations are better equipped to handle and mitigate risks associated with vulnerabilities like CVE-2025-21675.
Cloud security assessments should also be incorporated into the overall security strategy to address the evolving threat landscape effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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