Affected: Linux

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

phonet/pep: disable BH around forwarded sk_receive_skb()

The networking receive path is usually run from softirq context, but protocols that take the socket lock may have packets stored in the backlog and processed later from process context. In that case release_sock() -> __release_sock() drops the slock with spin_unlock_bh() and then calls sk->sk_backlog_rcv() with bottom halves enabled.

Typical sk_backlog_rcv handlers process the socket whose backlog is being drained, so the BH state at entry is irrelevant for the slocks they touch. pep_do_rcv() is different: when the inbound skb targets an existing PEP pipe, it forwards the skb to a different *child* socket via sk_receive_skb(). That helper takes the child slock with bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH is already off. The same child slock therefore ends up acquired with BH on (process path) and with BH off (softirq path):

process context softirq context --------------- --------------- release_sock(listener) __netif_receive_skb() __release_sock() phonet_rcv() spin_unlock_bh() __sk_receive_skb(listener) [BH now ENABLED] [BH already disabled] sk_backlog_rcv: sk_backlog_rcv: pep_do_rcv() pep_do_rcv() sk_receive_skb(child) sk_receive_skb(child…

Affected: Ubuntu:Pro:20.04:LTS: linux-hwe-5.15, Ubuntu:Pro:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-gcp, Ubuntu:22.04:LTS: linux-gke, Ubuntu:22.04:LTS: linux-gkeop, Ubuntu:22.04:LTS: linux-kvm, Ubuntu:22.04:LTS: linux-lowlatency, Ubuntu:22.04:LTS: linux-xilinx-zynqmp, Ubuntu:Pro:Realtime:22.04:LTS: linux-realtime and 1 more

Maxim Suhanov discovered that the NTFS file system implementation in the Linux kernel did not properly validate file name length in certain situations, leading to an out-of-bounds read. An attacker could use this to construct a malicious NTFS image that, when mounted and operated on, could expose sensitive information (kernel memory). (CVE-2023-45896)

It was discovered that some AMD processors did not properly clear data in the floating point divider unit during speculative execution. A local attacker could use this to expose sensitive information. (CVE-2025-54505)

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: - ARM32 architecture; - ARM64 architecture; - MIPS architecture; - PowerPC architecture; - S390 architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - ACPI drivers; - ATM drivers; - Drivers core; - Power management core; - DRBD Distributed Replicated Block Device drivers; - RNBD block device driver; - Bluetooth drivers; - Bus devices; - Character device driver; - TPM device driver; - Clocksource driv…