CVE-2025-21926 — net: gso: fix ownership in __udp_gso_segment

Affected: Linux, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

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

net: gso: fix ownership in __udp_gso_segment

In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug:

kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50

The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action:

1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug.

Fix this by also removing the reference to the socket in __udp_gso_segment.

USN-7510-1 — linux, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15…

Affected: Ubuntu:20.04:LTS: linux-ibm-5.15, Ubuntu:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:20.04:LTS: linux-oracle-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-gkeop, Ubuntu:22.04:LTS: linux-ibm, Ubuntu:22.04:LTS: linux-intel-iotg, Ubuntu:22.04:LTS: linux-kvm, Ubuntu:22.04:LTS: linux-lowlatency, Ubuntu:22.04:LTS: linux-nvidia and 1 more

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: - ARM64 architecture; - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Network block device driver; - Bus devices; - Character device driver; - TPM device driver; - Clock framework and drivers; - GPIO subsystem; - GPU drivers; - HID subsystem; - I2C subsystem; - InfiniBand drivers; - Media drivers; - NVIDIA Tegra memory controller driver; - Network drivers; - PCI subsystem; - PPS (Pulse Per Second) driver; - PTP clock framework; - RapidIO drivers; - Real Time Clock drivers; - SLIMbus drivers; - QCOM SoC drivers; - Trusted Execution Environment drivers; - TTY drivers; - USB DSL drivers; - USB Device Class drivers; - USB core drivers; - USB Gadget drivers; - USB Host Controller drivers; - Renesas USBHS Controller drivers; - ACRN Hypervisor Service Module driver; - File systems infrastructure; - BTRFS file system; - F2FS file system; - Network file system (NFS) server daemon; - NILFS2 file system; - Overlay file system; - SMB network file system; - UBI file system; - KVM subsystem; - L3 Master device support module; - Process Accounting mechanism; - Padata parallel execution mechanism; - printk logging mechanism; - Scheduler infrastructure; - Timer subsystem; - Tracing infrastructure…

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CVE-2025-21926 — net: gso: fix ownership in __udp_gso_segment

USN-7510-1 — linux, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15…