CVE-2026-64255 Linux CVE debrief

Who should care

Linux kernel users and administrators who use wifi iwlwifi mld, as well as security teams and vulnerability management teams responsible for ensuring the security and integrity of Linux kernel-based systems.

Technical summary

The Linux kernel's wifi iwlwifi mld has a vulnerability that can cause an out-of-bounds access when sta_mask is zero. The vulnerability is caused by the use of ffs(ba_data->sta_mask) - 1 to derive a station ID without checking that sta_mask is non-zero. This issue affects Linux kernel users and administrators who use wifi iwlwifi mld. To fix this vulnerability, WARN_ON_ONCE(!ba_data->sta_mask) guards are added before each ffs() call, consistent with the existing check in iwl_mld_ampdu_rx_start(). The HIGH severity of this vulnerability, with a CVSS score of 8.8, emphasizes the need for prompt action to mitigate this vulnerability.

Defensive priority

High priority due to HIGH severity and potential for out-of-bounds access. Linux kernel users and administrators should prioritize patching and verifying wifi iwlwifi mld configurations to prevent potential attacks. Compensating controls, such as monitoring and detection, should be reviewed for exposed systems while remediation is scheduled and verified. Asset inventory and rollback/change windows should also be considered to minimize potential impact. Source tracking and exposure review are essential to ensure that affected systems are properly addressed. Regular revalidation and testing of remediated assets are crucial to confirm the effectiveness of the patches and mitigations implemented. The CVSS score of 8.8 indicates a high level of severity, emphasizing the need for prompt action to mitigate this vulnerability. Linux kernel users and administrators should also consider the potential operational impact of this vulnerability and review the context of their specific environment to ensure that adequate measures are taken to prevent exploitation. By prioritizing patching and verification, Linux kernel users and administrators can minimize the risk associated with this vulnerability and maintain the security and integrity of their systems. The HIGH severity of this vulnerability underscores the importance of swift and effective mitigation to prevent potential attacks and minimize potential impact. Linux kernel users and administrators should work closely with their security teams to ensure that all necessary steps are taken to address this vulnerability and prevent future attacks. The use of compensating controls, such as monitoring and detection, can help to identify and respond to potential attacks in a timely and effective manner. By taking a proactive and comprehensive approach to mitigating this vulnerability, Linux kernel users and administrators can help to protect their systems and maintain the security and integrity of their environments. The importance of source tracking and exposure review cannot be overstated, as these measures can help to ensure that affected systems are properly addressed and that the risk associated with this vulnerability ismin

Recommended defensive actions

• Apply patches from official Linux kernel sources
• Verify and update wifi iwlwifi mld configurations
• Monitor for potential out-of-bounds access attempts
• Perform exposure review to identify potentially affected systems
• Implement compensating controls for exposed systems while remediation is scheduled and verified
• Conduct asset inventory to ensure all affected systems are properly addressed
• Track exceptions and retest remediated assets to confirm the effectiveness of the patches and mitigations implemented

Evidence notes

The CVE record was published on 2026-07-24T16:16:55.257Z and was last modified on 2026-07-27T05:16:37.810Z. The NVD entry is currently 8.8 HIGH. Linux kernel users should verify their systems for the wifi iwlwifi mld vulnerability and check for official patches. Evidence limits suggest that affected scope and severity details are based on vendor reports and may be subject to change as more information becomes available.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.