CVE-2026-53070

A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) over User Datagram Protocol (UDP) implementation. An issue with managing the transmission context across different processing units could lead to incorrect recursion level detection. This can cause network packets to be dropped, resulting in a Denial of Service (DoS) for affected systems.

SCTP over UDP transmit can call udp_tunnel_xmit_skb() or udp_tunnel6_xmit_skb() without bottom halves disabled. This can let execution move between CPUs while per CPU xmit recursion accounting is incremented and decremented, causing incorrect recursion level detection and packet drops in ip(6)_tunnel_xmit or __dev_queue_xmit. For the CVSS the PR:N is used for the paranoid score because a remote peer may trigger transmit on an exposed SCTP over UDP endpoint without local credentials. The issue is network reachable only when SCTP UDP encapsulation is enabled and usable by the attacker, which makes reliable triggering configuration dependent. Impact is denial of service through packet loss and degraded SCTP throughput, with no supported confidentiality or integrity impact from the patch context.

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.