Affected: AlmaLinux:8: bpftool, AlmaLinux:8: kernel, AlmaLinux:8: kernel-abi-stablelists, AlmaLinux:8: kernel-core, AlmaLinux:8: kernel-cross-headers, AlmaLinux:8: kernel-debug, AlmaLinux:8: kernel-debug-core, AlmaLinux:8: kernel-debug-devel, AlmaLinux:8: kernel-debug-modules, AlmaLinux:8: kernel-debug-modules-extra and 15 more

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

* kernel: mptcp: fix slab-use-after-free in __inet_lookup_established (CVE-2026-31669) * kernel: xen/privcmd: fix double free via VMA splitting (CVE-2026-31787) * kernel: Buffer overflow in drivers/xen/sys-hypervisor.c (CVE-2026-31786) * kernel: wifi: brcmfmac: validate bsscfg indices in IF events (CVE-2026-43110) * kernel: netfilter: flowtable: strictly check for maximum number of actions (CVE-2026-43329) * kernel: Bluetooth: hci_event: fix potential UAF in SSP passkey handlers (CVE-2026-46056) * kernel: wifi: mac80211: drop stray 'static' from fast-RX rx_result (CVE-2026-46152) * kernel: wifi: mac80211: remove station if connection prep fails (CVE-2026-46125)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

Important: kernel security, bug fix, and enhancement update

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

mptcp: fix slab-use-after-free in __inet_lookup_established

The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot have their slab caches created with this flag via proto_register().

However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init() (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point, tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently.

This causes MPTCP v6 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so when these sockets are freed without SOCK_RCU_FREE (which is cleared for child sockets by design), the memory can be immediately reused. Concurrent ehash lookups under rcu_read_lock can then access freed memory, triggering a slab-use-after-free in __inet_lookup_established.

Fix this by splitting the IPv6-specific initialization out of mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called from mptcp_proto_v6_init() before protocol registration. This ensures tcpv6_prot_override.slab correctly inherits the SLAB_TYPESAFE_BY_RCU slab cache.

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

mptcp: fix slab-use-after-free in __inet_lookup_established

The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot have their slab caches created with this flag via proto_register().

However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init() (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point, tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently.

This causes MPTCP v6 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so when these sockets are freed without SOCK_RCU_FREE (which is cleared for child sockets by design), the memory can be immediately reused. Concurrent ehash lookups under rcu_read_lock can then access freed memory, triggering a slab-use-after-free in __inet_lookup_established.

Fix this by splitting the IPv6-specific initialization out of mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called from mptcp_proto_v6_init() before protocol registration. This ensures tcpv6_prot_override.slab correctly inherits the SLAB_TYPESAFE_BY_RCU slab cache.

Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version V3.1.6 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant).

Siemens is preparing fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

kernel: mptcp: fix slab-use-after-free in __inet_lookup_established kernel: Buffer overflow in drivers/xen/sys-hypervisor.c kernel: xen/privcmd: fix double free via VMA splitting kernel: wifi: brcmfmac: validate bsscfg indices in IF events kernel: netfilter: flowtable: strictly check for maximum number of actions kernel: Bluetooth: hci_event: fix potential UAF in SSP passkey handlers kernel: wifi: mac80211: remove station if connection prep fails kernel: wifi: mac80211: drop stray 'static' from fast-RX rx_result

Affected: Rocky Linux:8: kernel

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

* kernel: mptcp: fix slab-use-after-free in __inet_lookup_established (CVE-2026-31669)

* kernel: xen/privcmd: fix double free via VMA splitting (CVE-2026-31787)

* kernel: Buffer overflow in drivers/xen/sys-hypervisor.c (CVE-2026-31786)

* kernel: wifi: brcmfmac: validate bsscfg indices in IF events (CVE-2026-43110)

* kernel: netfilter: flowtable: strictly check for maximum number of actions (CVE-2026-43329)

* kernel: Bluetooth: hci_event: fix potential UAF in SSP passkey handlers (CVE-2026-46056)

* kernel: wifi: mac80211: drop stray 'static' from fast-RX rx_result (CVE-2026-46152)

* kernel: wifi: mac80211: remove station if connection prep fails (CVE-2026-46125)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version V3.1.6 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant).

Siemens has released new versions for several affected products and recommends to update to the latest versions. Siemens is preparing further fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

Security update for the Linux Kernel

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 180 more

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix slab-use-after-free in __inet_lookup_established The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot have their slab caches created with this flag via proto_register(). However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init() (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point, tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently. This causes MPTCP v6 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) instead of the TCPv6 slab cache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so when these sockets are freed without SOCK_RCU_FREE (which is cleared for child sockets by design), the memory can be immediately reused. Concurrent ehash lookups under rcu_read_lock can then access freed memory, triggering a slab-use-after-free in __inet_lookup_established. Fix this by splitting the IPv6-specific initialization out of mptcp_subflow_init() into a new mptcp_subflow_v6_init(), called from mptcp_proto_v6_init() before protocol registration. This ensures tcpv6_prot_override.slab correctly inherits the SLAB_TYPESAFE_BY_RCU slab cache.

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um nicht näher spezifizierte Angriffe durchzuführen, welche zu einem Denial-of-Service-Zustand, einer Rechteausweitung, der Ausführung von Code oder einer Speicherbeschädigung führen könnten.