CVE-2026-23447 Linux CVE debrief

Who should care

Linux kernel users and administrators should be aware of this vulnerability and take steps to mitigate it. This includes updating to a patched version of the Linux kernel. Linux kernel users and administrators should prioritize patching or applying mitigations to prevent potential exploitation. This includes updating to a patched version of the Linux kernel and reviewing compensating controls for exposed systems while remediation is scheduled and verified. Monitoring for potential exploitation attempts is also recommended.

Technical summary

The vulnerability exists in the cdc_ncm_rx_verify_ndp32() function of the Linux kernel. The function does not properly validate the size of the DPE array against the total skb length, allowing for out-of-bounds reads. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. The patch adds ndpoffset to the nframes bounds check and uses struct_size_t() to express the NDP-plus-DPE-array size more clearly.

Defensive priority

High, based on CVSS score of 7.8 and potential for out-of-bounds reads in the Linux kernel's cdc_ncm_rx_verify_ndp32() function, indicating a need for immediate attention and mitigation through patching or compensating controls for exposed systems. Linux kernel users and administrators should prioritize patching or applying mitigations to prevent potential exploitation. This includes updating to a patched version of the Linux kernel and reviewing compensating controls for exposed systems while remediation is scheduled and verified. Monitoring for potential exploitation attempts is also recommended. The vulnerability's high severity and potential impact on Linux kernel users and administrators necessitate a high defensive priority to minimize potential damage and ensure system security. Therefore, it is crucial to review and apply the provided patches, monitor for potential exploitation attempts, and track exceptions, retest remediated assets, and close the item only after evidence is documented. Additionally, defenders should verify the patch implementation and ensure that the systems are properly configured to prevent exploitation. By taking these steps, Linux kernel users and administrators can effectively mitigate the vulnerability and minimize potential risks. Furthermore, it is essential to consider the vulnerability's potential impact on the overall system security and take a proactive approach to prevent potential exploitation. This includes regularly reviewing and updating the system's security configurations, monitoring for potential security threats, and implementing additional security measures as needed. By prioritizing the vulnerability's mitigation and taking a proactive approach to system security, Linux kernel users and administrators can minimize potential risks and ensure the security of their systems. The vulnerability's high defensive priority highlights the need for prompt action to prevent potential exploitation and minimize potential damage. Therefore, Linux kernel users and administrators should take immediate action to mitigate the vulnerability and ensure system security. This includes prioritizing patching or applying mitigations, as a

Recommended defensive actions

• Update to a patched version of the Linux kernel
• Review and apply the provided patches
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability was resolved with a patch that adds ndpoffset to the nframes bounds check and uses struct_size_t() to express the NDP-plus-DPE-array size more clearly. The patch was applied to the Linux kernel stable branches. Linux kernel users should verify their systems for exposure and apply patches or mitigations as needed. Evidence is limited to CVE and NVD details.

Official resources