In the Linux kernel, the following vulnerability has been resolved: xfrm: add NULL check in xfrm_update_ae_params. Normally, x->replay_esn and x->preplay_esn should be allocated at xfrm_alloc_replay_state_esn(...) in xfrm_state_construct(...), hence the xfrm_update_ae_params(...) is okay to update them. However, the current implementation of xfrm_new_ae(...) allows a malicious user to directly dereference a NULL pointer and crash the kernel.
With a CVSS score of 5.5, this vulnerability is classified as medium severity. The impact primarily affects availability, as it can lead to kernel crashes. Given its nature, organizations using affected versions of the Linux kernel should prioritize patching immediately.
Risk to organizations includes potential service disruptions and instability of systems running the Linux kernel. The vulnerability allows attackers to exploit a NULL pointer dereference, leading to an unexpected kernel panic. Organizations should assess their environments to determine if they are running vulnerable versions and take action accordingly.
Currently, this vulnerability does not have any known exploits or public proof of concepts available. However, the nature of the vulnerability suggests that it could be leveraged in targeted attacks, particularly against systems with low security hardening.
Organizations should schedule remediation to ensure they are protected from potential exploitation. Patching should be done as part of the regular update cycle.
Vulnerability Details
This vulnerability allows attackers to cause a denial of service through a kernel crash. The CVSS score of 5.5 indicates that while it’s not the highest severity, it still poses a significant risk to systems that are not patched. The vulnerability was published on September 15, 2025, and is classified under CWE-476, which relates to NULL pointer dereferences.
Technical Analysis
The root cause of this vulnerability is a lack of NULL pointer validation in the xfrm_update_ae_params function. When xfrm_new_ae is called, it can lead to a NULL dereference, resulting in a kernel panic. The attack vector is local, requiring low privileges, and no user interaction is necessary. This vulnerability highlights the importance of proper input validation in system-level programming.
Risk & Impact Analysis
Real-world deployment risk is moderate given that the vulnerability can only be exploited locally by users with low privileges. The impact on availability is high, meaning that systems could become unresponsive and require a restart. This vulnerability can be significant for organizations relying on the Linux kernel for critical services.
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 2.6.39 up to but excluding 4.14.324, as well as versions from 4.15 up to 4.19.293, and several others through to version 6.4.12. For the most secure environment, it is recommended to upgrade to the latest stable version.
Mitigation & Remediation
Organizations should apply relevant patches immediately. For users running vulnerable versions of the Linux kernel, upgrading to a secure version is critical. If immediate patching is not feasible, consider implementing network controls and monitoring to mitigate exposure.
Detection Guidance
Monitor system logs for indications of unexpected kernel panics or instability. Behavioral anomalies, such as unusual system crashes, should be investigated promptly. Network signatures associated with exploit attempts may also be useful for detection.
AppSecure Threat Intelligence Insight
This vulnerability serves as a reminder of the importance of thorough input validation in kernel-level programming. Security teams should note the potential for such vulnerabilities to lead to denial of service attacks and consider proactive measures to enhance kernel security. For more insights into securing Linux environments, refer to the relevant resources on Linux security assessment. Additionally, organizations should review their vulnerability management practices to ensure timely patching and remediation.
For further reading on vulnerability assessments and penetration testing best practices, organizations can refer to the following guides: vulnerability management program design, penetration testing methodology, and continuous security testing to enhance their 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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