In the Linux kernel, a high-severity vulnerability has been identified, classified as CVE-2025-21631. This vulnerability allows for a use-after-free condition, specifically within the block, bfq subsystem. The issue arises from a flaw in the bfq_split_bfqq function, which can lead to significant security risks if not addressed.
The CVSS score for this vulnerability is 7.8, indicating a high severity level. Given the potential for exploitation, organizations should prioritize patching immediately. The vulnerability was published on January 19, 2025, and has been modified since its initial disclosure.
Risk to organizations includes unauthorized access and potential system compromise. The exploitation of this vulnerability could allow attackers to execute arbitrary code with elevated privileges. It is crucial for organizations using affected versions of the Linux kernel to take immediate action to protect their systems.
As of now, there is no public exploit confirmed, but the potential impact of this vulnerability necessitates urgent attention from security teams.
Vulnerability Details
The official description of the vulnerability indicates that it is a use-after-free issue in the Linux kernel's bfq subsystem. This problem has been confirmed in various versions of the kernel, particularly versions between 5.15.168 and 5.15.177, 6.1.113 to 6.1.125, and 6.6.54 to 6.6.72, among others.
The vulnerability was discovered during routine testing by syzkaller, which reported a slab-use-after-free condition. Specific call traces indicate the vulnerability's location within the kernel code during memory allocation and request processing.
The associated CWE classification is CWE-416, which pertains to use-after-free vulnerabilities. This class of vulnerabilities can lead to significant security risks, allowing attackers to exploit memory management flaws.
Technical Analysis
The root cause of this vulnerability is a failure in memory management within the Linux kernel, specifically in the bfq block IO scheduler. The attack vector is local, meaning that an attacker must have local access to the system to exploit this flaw. The attack complexity is low, and the attacker requires low privileges to leverage this vulnerability.
User interaction is not required for successful exploitation, which further increases the risk. The potential impacts of this vulnerability are severe, with high confidentiality, integrity, and availability impacts indicated by the CVSS score.
Risk & Impact Analysis
The real-world deployment risk associated with this vulnerability is significant, given its potential for exploitation in local environments. Organizations utilizing affected versions of the Linux kernel must understand the implications of an attacker gaining elevated privileges through this vulnerability.
The urgency for remediation is underscored by the high CVSS score and the potential effects on system integrity. Organizations should address this vulnerability in their priority patch cycle to mitigate risks.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects multiple versions of the Linux kernel, specifically versions from 5.15.168 to 5.15.177, 6.1.113 to 6.1.125, and 6.6.54 to 6.6.72, as well as several release candidates of version 6.13.
Mitigation & Remediation
Organizations should prioritize patching to the latest versions of the Linux kernel to remediate this vulnerability. Specific patches have been released that address this issue, and organizations must ensure they are applied promptly.
In case the patches are not immediately available, organizations may consider implementing configuration hardening techniques and monitoring for unusual behavior that could indicate exploitation attempts.
Continuous security testing can also help identify and mitigate vulnerabilities in a timely manner.
Detection Guidance
Monitoring logs for indicators of exploitation attempts is crucial. Look for unusual memory allocation patterns, unexpected task behavior, and anomalies in system logs that could indicate attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
This vulnerability underscores the importance of robust memory management in system kernels and highlights ongoing challenges in maintaining secure software environments. Security teams should prioritize regular updates and vulnerability assessments to mitigate risks effectively.
For organizations utilizing Linux systems, implementing a comprehensive application security assessment can help identify vulnerabilities and improve overall security posture.
Additionally, engaging in continuous penetration testing can provide ongoing insights into the security landscape and help organizations stay ahead of potential threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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