CVE-2026-23003

Published Jan 25, 2026

Last updated 5 days ago

CVSS high 7.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() Blamed commit did not take care of VLAN encapsulations as spotted by syzbot [1]. Use skb_vlan_inet_prepare() instead of pskb_inet_may_pull(). [1] BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] BUG: KMSAN: uninit-value in IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 ip6ip6_dscp_ecn_decapsulate+0x16f/0x1b0 net/ipv6/ip6_tunnel.c:729 __ip6_tnl_rcv+0xed9/0x1b50 net/ipv6/ip6_tunnel.c:860 ip6_tnl_rcv+0xc3/0x100 net/ipv6/ip6_tunnel.c:903 gre_rcv+0x1529/0x1b90 net/ipv6/ip6_gre.c:-1 ip6_protocol_deliver_rcu+0x1c89/0x2c60 net/ipv6/ip6_input.c:438 ip6_input_finish+0x1f4/0x4a0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x9c/0x330 net/ipv6/ip6_input.c:500 ip6_mc_input+0x7ca/0xc10 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6139 [inline] __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252 netif_receive_skb_internal net/core/dev.c:6338 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6397 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4960 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586 __alloc_skb+0x805/0x1040 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995 tun_alloc_skb drivers/net/tun.c:1461 [inline] tun_get_user+0x1142/0x6c60 drivers/net/tun.c:1794 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6465 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-908
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-457

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Check write tracking in all address spaces kvm_gfn_is_write_tracked() checks only the supplied memslot, but page tracking is per-address-space and shadow pages are shared across all address spaces. With SMM, a GFN can therefore be write-tracked in one address space and appear untracked through the other. Check the supplied slot first, then the slot for the other address space. This ensures all callers honor write tracking regardless of the active address space. In particular, it prevents mmu_try_to_unsync_pages() from marking an upper-level shadow page unsync and eventually triggering the BUG in pte_list_remove(). [invert direction of the conditional. - Paolo]•CVE-2026-98164
  2. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163
  3. In the Linux kernel, the following vulnerability has been resolved: smb/server: fix tree connection leak in smb2_tree_connect() See the procedure below: smb2_tree_connect ksmbd_tree_conn_connect xa_store(&sess->tree_conns, tree_conn->id, tree_conn) ksmbd_counter_inc(KSMBD_COUNTER_TREE_CONNS) ksmbd_share_tree_conn_inc(sc) ksmbd_iov_pin_rsp // fail status.ret = KSMBD_TREE_CONN_STATUS_NOMEM // do not disconnect tree_conn Disconnect the new tree connection if ksmbd_iov_pin_rsp() fails.•CVE-2026-98162
  4. In the Linux kernel, the following vulnerability has been resolved: nvdimm: pmem: keep PREFLUSH before data writes pmem_submit_bio() records a REQ_PREFLUSH error, but continues to copy the bio data and can later overwrite the error with a successful REQ_FUA flush. That lets data writes run after a failed preflush and can complete the bio successfully despite the failed ordering barrier. Run the REQ_PREFLUSH flush synchronously before touching the bio data and complete the bio with the flush error if it fails. Keep asynchronous flush chaining for REQ_FUA. At that point, data copy has completed and the parent bio can wait for the chained flush bio.•CVE-2026-98161
  5. In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix mismatched free of HalData in rtw_sdio_if1_init() padapter->HalData is allocated via vzalloc(), but incorrectly freed using kfree() in the rtw_sdio_if1_init() error path. Using kfree() to release this vmalloc-backed buffer can lead to memory corruption. Use rtw_hal_data_deinit() to pair the free correctly and free HalData with vfree(). The bug was first flagged by an experimental static analysis tool we are developing for kernel memory-management bugs. Manual inspection confirms that the issue is still present in current mainline. An x86_64 allyesconfig build showed no new warnings. As we do not have suitable RTL8723BS SDIO hardware to test with, no runtime testing was able to be performed.•CVE-2026-98160

References

Sources include official advisories and independent security research.