In the Linux kernel, a significant vulnerability has been addressed, identified as CVE-2025-21692. This vulnerability arises from an issue in the ETS (Enhanced Transmission Selection) queuing discipline, where the function ets_class_from_arg() can index an Out-Of-Bound (OOB) class when passed a class ID (clid) of 0. The potential for this overflow can lead to local privilege escalation, which poses a serious threat to system integrity. The vulnerability was reported by Haowei Yan.
The severity of this vulnerability is classified as high, with a CVSS score of 7.8. This score reflects the potential impact on confidentiality, integrity, and availability, all rated as high. Given the nature of this vulnerability, it is imperative for organizations to prioritize patching their systems to prevent exploitation.
As of the latest update, there is no confirmed public exploit available, and the vulnerability is not listed in the Known Exploited Vulnerabilities (KEV) database. However, organizations should remain vigilant and take immediate action to mitigate any risks associated with this vulnerability.
Organizations should prioritize patching immediately to mitigate risks associated with this vulnerability, especially considering its potential for privilege escalation.
Vulnerability Details
CVE-2025-21692 affects the Linux kernel, specifically related to the Enhanced Transmission Selection (ETS) queuing discipline. The overflow issue can be triggered by passing a class ID of 0 to the function ets_class_from_arg(). This vulnerability has been assigned a CVSS score of 7.8, with the following vector string: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
This vulnerability was published on February 10, 2025, and has been classified under CWE-129, which refers to improper validation of array index. Given the CVSS metrics indicating local attack vector, low attack complexity, and low privileges required, the potential for exploitation increases significantly.
Technical Analysis
The root cause of this vulnerability lies in the improper validation of the class ID input, allowing indexing beyond the allocated bounds of the ETS class array. Attackers with local access can exploit this vulnerability to escalate privileges, potentially gaining unauthorized access to system resources.
The attack vector is local, requiring an attacker to have physical or remote access to the affected system. The complexity of the attack is low, as it does not require any user interaction. The impact on confidentiality, integrity, and availability is rated as high, indicating that successful exploitation can severely compromise the system.
Risk & Impact Analysis
The real-world risk of CVE-2025-21692 is significant, particularly for organizations running vulnerable versions of the Linux kernel. The potential for local privilege escalation means that attackers could gain elevated access to sensitive system areas, leading to data breaches or system integrity violations. The implications extend beyond individual systems, potentially affecting entire networks if attackers can pivot from compromised systems.
Organizations should address this vulnerability in their priority patch cycle. The urgency is underscored by the high severity rating and the potential for exploitation. Given the ongoing threat landscape, timely remediation is essential to maintain robust security postures.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects Linux kernel versions from 5.6 up to, but not including, 5.10.234, as well as versions from 5.11 up to, but not including, 5.15.178, 5.16 up to, but not including, 6.1.128, 6.2 up to, but not including, 6.6.75, and 6.7 up to, but not including, 6.12.12. Additionally, it affects version 6.13 and its release candidates (rc1 to rc7).
Mitigation & Remediation
To address CVE-2025-21692, organizations should apply the latest Linux kernel patches available. For specific patch details, refer to Linux kernel patch documentation. If immediate patching is not feasible, consider implementing network controls to limit access to affected systems and monitor for any unusual activity that may indicate exploitation attempts.
Detection Guidance
Security teams should monitor system logs for any indicators of exploitation attempts related to this vulnerability. Look for log entries that indicate out-of-bounds access attempts or other anomalies in system behavior that may suggest privilege escalation activities.
AppSecure Threat Intelligence Insight
CVE-2025-21692 highlights the ongoing need for organizations to maintain a proactive approach towards vulnerability management. With the introduction of new vulnerabilities, security teams must adapt their strategies to mitigate risks effectively. Continuous security assessments, such as continuous penetration testing, are essential to identify and remediate weaknesses before they can be exploited.
Organizations should also consider establishing a robust incident response plan to address any potential exploitation of vulnerabilities like CVE-2025-21692. By investing in red teaming services, organizations can better prepare for the evolving threat landscape.
Finally, staying informed about trends in vulnerability exposure and remediation strategies is crucial. Regularly reviewing resources such as the vulnerability management program can help organizations maintain an effective 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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