In the Linux kernel, a vulnerability identified as CVE-2025-21674 has been reported, which involves issues related to the IPsec tunnel functionality. This vulnerability allows for the possibility of a kernel panic when attempting to enable IPsec packet offload in tunnel mode, especially in debug kernels. The root cause stems from two main issues within the code: the incorrect variant usage in the SA add section and an unnecessary flush_workqueue in the SA delete routine.
The vulnerability has a CVSS score of 5.5, classifying it as medium severity. The documented risks to organizations include potential disruption of services due to kernel panic, which can lead to denial of service conditions. Given the nature of this vulnerability, it is crucial for organizations to address this issue as part of their priority patch cycle.
Currently, there are no known exploits in the wild for this vulnerability, and it has not been included in the Known Exploited Vulnerabilities (KEV) catalog. However, the urgency for patching remains, especially considering the implications of a kernel panic on system stability.
Organizations should prioritize patching immediately to ensure the stability and security of their systems against this vulnerability.
Vulnerability Details
As detailed in the official CVE description, the vulnerability affects the Linux kernel's IPsec functionality. The specific issues leading to the kernel panic include the need for a correct function variant in the SA add section and the removal of the unnecessary flush_workqueue in the SA delete routine.
The CVSS score of 5.5 indicates a medium level of risk, with the vulnerability classified under CWE-667, which pertains to improper resource shutdown. The affected product is the Linux kernel, particularly versions from 6.4 up to but not including 6.6.74, and other specified release candidates.
The vulnerability was published on January 31, 2025, and has been modified in subsequent reports.
Technical Analysis
The root cause of CVE-2025-21674 lies in the incorrect handling of locks within the IPsec implementation of the kernel. Specifically, an attempt to enable IPsec packet offload in tunnel mode results in a deadlock situation due to improper lock ordering between SOFTIRQ-safe and SOFTIRQ-unsafe locks.
The attack vector is classified as local, meaning that an attacker would need local access to exploit this vulnerability. The attack complexity is low, requiring minimal effort to trigger the conditions leading to a kernel panic.
No user interaction is required, and the impact on availability is high, as the kernel panic can lead to a complete halt of the affected system.
Risk & Impact Analysis
The real-world risk associated with CVE-2025-21674 is significant, particularly for organizations relying on the Linux kernel for critical infrastructure. The potential for a kernel panic poses a serious threat, as it can lead to downtime and loss of service. Given the medium severity rating, organizations should assess their exposure and prioritize remediation efforts accordingly.
The blast radius for this vulnerability could extend to any systems using the affected versions of the Linux kernel, emphasizing the need for swift action to mitigate risks.
Urgency for remediation should be classified as high, as the vulnerability may affect many systems due to the widespread usage of the Linux kernel. Organizations should map out their patching strategies to include this update.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the Linux kernel include all versions from 6.4 up to but not including 6.6.74, as well as versions 6.7 to 6.12.11. Specific release candidates (6.13:rc1 to 6.13:rc7) are also vulnerable.
Mitigation & Remediation
Organizations should apply the patches provided in the references to remediate this vulnerability. It’s essential to update to the latest available version of the Linux kernel, specifically versions that are not impacted by this vulnerability.
In the case where a patch cannot be immediately applied, organizations should consider implementing configuration hardening and network controls to limit exposure.
Monitoring systems for abnormal behavior during this window can help identify potential exploitation attempts.
Continuous security testing can also be beneficial to ensure ongoing protection against vulnerabilities.
Detection Guidance
To detect potential exploitation attempts related to this vulnerability, organizations should monitor logs for indicators such as abnormal kernel messages, particularly those related to IPsec functionality.
Behavioral anomalies in system performance should also be investigated, especially during operations involving IPsec tunnels.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-21674 reflects ongoing challenges in kernel development, particularly around security and stability. This vulnerability underscores the importance of rigorous testing and validation processes in development lifecycles.
Security teams should take this incident as a learning opportunity to enhance their defensive strategies, ensuring that similar vulnerabilities are identified and mitigated in future kernel updates.
Vulnerability management programs play a critical role in maintaining security posture and should be continually updated to reflect the latest threat landscape.
Penetration testing methodologies can help to uncover similar vulnerabilities that may not yet be disclosed.
Cloud penetration testing is also essential for organizations utilizing cloud services, as it can help identify risks associated with kernel vulnerabilities in virtual environments.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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