CVE-2026-74666

A flaw was found in the Linux kernel's packet subsystem. This vulnerability occurs due to improper synchronization during ring reconfiguration, where the system can attempt to access memory that has already been freed or is invalid. This can lead to a system crash, resulting in a Denial of Service (DoS) for the affected system.

AF_PACKET ring reconfiguration can race with packet_recvmsg or packet_poll pressure clearing. The socket may still observe tpacket_rcv after the RX ring has been cleared, so __packet_rcv_has_room can dereference stale or NULL ring storage. This is a local control plane race on packet socket ring state rather than a remotely reachable packet input bug. For the CVSS the PR:L is used because a local process with AF_PACKET access, CAP_NET_RAW, or equivalent delegated network namespace capability is needed to create and reconfigure the packet ring. Impact is at least local denial of service via kernel crash.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.