CVE-2026-52942 Linux CVE debrief

Who should care

Linux kernel developers, maintainers, and users who rely on the netfilter component should be aware of this vulnerability. Additionally, security teams and administrators responsible for Linux-based systems should take note of this vulnerability and assess their exposure.

Technical summary

The vulnerability is caused by the dump_mac_header function not properly validating the MAC header before dumping it. The function checks only if skb->mac_header != skb->network_header, without verifying if the MAC header was set using skb_mac_header_was_set(). This can lead to an out-of-bounds read of up to 64 KiB past the buffer. The vulnerability can be triggered via the netdev logger, specifically through the nf_log_unknown_packet function, which calls dump_mac_header unconditionally.

Defensive priority

High priority should be given to patching this vulnerability, as it can be exploited to read sensitive information from the kernel memory. Linux kernel developers and maintainers should apply the provided patches to mitigate this vulnerability.

Recommended defensive actions

• Apply the official patches provided by the Linux kernel maintainers.
• Review and update Linux kernel configurations to ensure that the netfilter component is properly secured.
• Monitor system logs for potential exploitation attempts.
• Perform regular vulnerability assessments and penetration testing to identify potential weaknesses.
• Consider implementing additional security controls, such as SELinux or AppArmor, to enhance system security.

Evidence notes

The vulnerability was discovered and reported by an unknown researcher. The CVE record was published on June 24, 2026, and updated on June 28, 2026. The NVD detail page provides additional information about the vulnerability, including its CVSS score and vector.

Official resources