In the Linux kernel, a high-severity vulnerability has been identified that could lead to out-of-bounds memory access due to a logic error in the scheduling component, specifically within the sch_cake implementation. The issue arises from the failure to properly handle the per-host bulk flow counters, which can be triggered through local access. This vulnerability has been classified with a CVSS score of 7.1, indicating its potential impact on confidentiality and availability.
Risk to organizations includes significant disruption to system availability and potential unauthorized access to sensitive information. The urgency for defenders is high, as immediate remediation is required to prevent exploitation of this vulnerability.
As of the latest updates, there are no known exploits available for this vulnerability, but the underlying issues could lead to serious consequences if left unaddressed. Organizations should prioritize patching this vulnerability as part of their security management processes.
To mitigate the risks associated with CVE-2025-21647, organizations are advised to apply the relevant patches provided by the Linux kernel maintainers and to review their systems for any signs of abnormal activity related to memory access.
Vulnerability Details
The vulnerability allows for out-of-bounds memory access due to improper handling of host bulk flow fairness counts within the sch_cake scheduler. The CVSS score of 7.1 denotes a high severity level, indicating a substantial risk to systems running affected versions of the Linux kernel. The vulnerability was published on January 19, 2025, and is classified under CWE-125.
Technical Analysis
The root cause of this vulnerability stems from a logic error in the scheduling component, which failed to implement proper bounds checks on the per-host bulk flow counters. The attack vector is local, meaning that an attacker must have local access to the system to exploit this vulnerability. The attack complexity is classified as low, and it requires low privileges but does not require user interaction.
The confidentiality impact is high, while integrity impact is none. Availability may also be severely affected due to potential memory corruption. The consolidated flow quantum calculation, which has been moved into helper functions, improves readability and reduces the likelihood of similar errors in the future.
Risk & Impact Analysis
The real-world risk associated with CVE-2025-21647 is significant due to the potential for attackers to exploit the memory access vulnerabilities, leading to unauthorized data exposure and system instability. Organizations should assess their deployments to identify any systems running vulnerable versions of the Linux kernel and prioritize patching them. The blast radius could extend to any service relying on the affected kernel versions, amplifying the urgency to remediate this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Affected versions of the Linux kernel include all versions from 5.4.284 to 5.4.290, 5.10.226 to 5.10.234, 5.15.167 to 5.15.178, 6.1.110 to 6.1.124, 6.6.51 to 6.6.71, 6.10.10 to 6.11, and 6.11.1 to 6.12.9. Organizations should ensure they are using patched versions to avoid this vulnerability.
Mitigation & Remediation
Organizations should prioritize patching their Linux kernels to versions that address this vulnerability. For detailed remediation processes, organizations can refer to resources on penetration testing to identify any similar weaknesses in their systems. It is essential to apply patches as soon as they are available and to review configurations to ensure they are hardened against such vulnerabilities.
Detection Guidance
Organizations should monitor logs for indicators of out-of-bounds memory access and other related anomalies. Behavioral changes in system performance or abnormal access patterns may serve as indicators of exploitation attempts. Network signatures that reflect inappropriate memory access attempts should also be established.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-21647 lies in the importance of rigorous code reviews and testing in the development process of the Linux kernel. This incident highlights a trend where vulnerabilities related to memory access continue to pose risks, emphasizing the need for improved security practices. Security teams should consider adopting a vulnerability management program to proactively address such vulnerabilities in the future. Furthermore, continuous training and updates on secure coding practices should be prioritized within development teams.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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