CVE-2026-53070 — sctp: disable BH before calling udp_tunnel_xmit_skb()

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

sctp: disable BH before calling udp_tunnel_xmit_skb()

udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to tunnel xmit functions"), on the path:

udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit()

dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU.

Without local_bh_disable(), the context may move between CPUs, which can break the inc/dec pairing. This may lead to incorrect recursion level detection and cause packets to be dropped in ip(6)_tunnel_xmit() or __dev_queue_xmit().

Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths.

In my testing, after enabling the SCTP over UDP:

# ip net exec ha sysctl -w net.sctp.udp_port=9899 # ip net exec ha sysctl -w net.sctp.encap_port=9899 # ip net exec hb sysctl -w net.sctp.udp_port=9899 # ip net exec hb sysctl -w net.sctp.encap_port=9899

# ip net exec ha iperf3 -s

- without this patch:

# ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender [ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver

- with this patch:

# ip net exec hb iperf3 -c 192.168.0.1 --sctp [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender [ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver

USN-8566-1 — linux, linux-gcp, linux-gke, linux-realtime vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-gke, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some AMD Zen 2 processors did not properly isolate shared resources in the operation cache. A local attacker could possibly use this issue to corrupt instructions executed at a higher privilege level, resulting in privilege escalation. (CVE-2025-54518)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - PSP security protocol; - ARM64 architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Intel NPU Driver; - DRBD Distributed Replicated Block Device drivers; - Ublk userspace block driver; - Bluetooth drivers; - Bus devices; - Character device driver; - Clock framework and drivers; - CPU frequency scaling framework; - Hardware crypto device drivers; - EDAC drivers; - EFI core; - FWCTL subsystem; - GPU drivers; - HID subsystem; - I3C subsystem; - InfiniBand drivers; - IOMMU subsystem; - Mailbox framework; - Multiple devices driver; - Media drivers; - NVIDIA Tegra memory controller driver; - MTD block device drivers; - Network drivers; - Ethernet bonding driver; - Mellanox network drivers; - Microsoft Azure Network Adapter (MANA) driver; - STMicroelectronics network drivers; - MediaTek network drivers; - NVME drivers; - PCI subsystem;…

Most recent entries from all

CVE-2026-53070 — sctp: disable BH before calling udp_tunnel_xmit_skb()

USN-8566-1 — linux, linux-gcp, linux-gke, linux-realtime vulnerabilities