CVE-2026-74476 Linux CVE debrief

Who should care

Linux kernel developers, administrators, and users who rely on the Linux kernel for their systems, especially those responsible for maintaining and securing Linux-based infrastructure, should be aware of this vulnerability and take necessary actions to mitigate its impact. This includes reviewing system configurations, assessing potential exposure, and implementing compensating controls where necessary. Additionally, security teams and vulnerability management teams should prioritize patching and monitoring for potential exploitation attempts. Linux distribution maintainers and security researchers may also be interested in the technical details of this vulnerability and its resolution. Furthermore, organizations using Linux-based systems in their products or services should evaluate the vulnerability's impact on their offerings and take appropriate measures to protect their customers. The vulnerability's resolution and mitigation strategies should be communicated to relevant stakeholders, including system administrators, security teams, and end-users, to ensure a coordinated response to the vulnerability. IT service providers and managed security service providers may also need to review and update their services to address this vulnerability in their clients' systems. Lastly, Linux kernel contributors and maintainers may be interested in the technical changes made to resolve this vulnerability and how they can improve the kernel's security posture in the future. The vulnerability affects Linux kernel versions and may impact various Linux distributions, so users of these distributions should also be aware of the vulnerability and take necessary actions. The vulnerability has been resolved in the Linux kernel, and users can apply vendor patches or updates to resolve the vulnerability. The vulnerability's impact can be mitigated by implementing compensating controls, such as monitoring for potential exploitation attempts and reviewing system configurations. The vulnerability's resolution and mitigation strategies should be documented and shared with relevant stakeholders to ensure a coordinated response to the vulnerability. The Linux kernel community and Linux

Technical summary

The Linux kernel vulnerability CVE-2026-74476 occurs when a frag_list skb reaches veth with data_len set but nr_frags zero. The veth_convert_skb_to_xdp_buff() function only converts skbs that are shared, locked, have frags[], or do not have enough headroom. This exposes frag_list data to XDP as if it were stored in frags[], but frags[] is empty. To resolve this, non-linear skbs are routed through skb_pp_cow_data() before exposing them to XDP, and XDP frags are only advertised when the resulting skb has frags[].

Defensive priority

Medium

Recommended defensive actions

• Inventory and assess Linux kernel versions for potential vulnerability
• Apply vendor patches or updates to resolve the vulnerability
• Monitor for potential exploitation attempts
• Implement compensating controls to mitigate potential impact
• Review system configurations and assess potential exposure
• Implement monitoring and detection for potential exploitation attempts
• Track exceptions and retest remediated assets

Evidence notes

The vulnerability allows non-linear skbs to be routed through skb_pp_cow_data() before exposing them to XDP. This prevents AF_XDP copy mode from trusting bogus XDP fragment metadata and crashing in memcpy() from __xsk_rcv(). To verify, defenders should review the Linux kernel versions for potential vulnerability, assess the impact of the vulnerability on their systems, and apply vendor patches or updates to resolve the vulnerability.

Official resources