CVE-2023-53634

Published Oct 7, 2025

Last updated 9 months ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fixed a BTI error on returning to patched function When BPF_TRAMP_F_CALL_ORIG is set, BPF trampoline uses BLR to jump back to the instruction next to call site to call the patched function. For BTI-enabled kernel, the instruction next to call site is usually PACIASP, in this case, it's safe to jump back with BLR. But when the call site is not followed by a PACIASP or bti, a BTI exception is triggered. Here is a fault log: Unhandled 64-bit el1h sync exception on CPU0, ESR 0x0000000034000002 -- BTI CPU: 0 PID: 263 Comm: test_progs Tainted: GF Hardware name: linux,dummy-virt (DT) pstate: 40400805 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c) pc : bpf_fentry_test1+0xc/0x30 lr : bpf_trampoline_6442573892_0+0x48/0x1000 sp : ffff80000c0c3a50 x29: ffff80000c0c3a90 x28: ffff0000c2e6c080 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000050 x23: 0000000000000000 x22: 0000ffffcfd2a7f0 x21: 000000000000000a x20: 0000ffffcfd2a7f0 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffcfd2a7f0 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: ffff80000914f5e4 x9 : ffff8000082a1528 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0101010101010101 x5 : 0000000000000000 x4 : 00000000fffffff2 x3 : 0000000000000001 x2 : ffff8001f4b82000 x1 : 0000000000000000 x0 : 0000000000000001 Kernel panic - not syncing: Unhandled exception CPU: 0 PID: 263 Comm: test_progs Tainted: GF Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0xec/0x144 show_stack+0x24/0x7c dump_stack_lvl+0x8c/0xb8 dump_stack+0x18/0x34 panic+0x1cc/0x3ec __el0_error_handler_common+0x0/0x130 el1h_64_sync_handler+0x60/0xd0 el1h_64_sync+0x78/0x7c bpf_fentry_test1+0xc/0x30 bpf_fentry_test1+0xc/0x30 bpf_prog_test_run_tracing+0xdc/0x2a0 __sys_bpf+0x438/0x22a0 __arm64_sys_bpf+0x30/0x54 invoke_syscall+0x78/0x110 el0_svc_common.constprop.0+0x6c/0x1d0 do_el0_svc+0x38/0xe0 el0_svc+0x30/0xd0 el0t_64_sync_handler+0x1ac/0x1b0 el0t_64_sync+0x1a0/0x1a4 Kernel Offset: disabled CPU features: 0x0000,00034c24,f994fdab Memory Limit: none And the instruction next to call site of bpf_fentry_test1 is ADD, not PACIASP: <bpf_fentry_test1>: bti c nop nop add w0, w0, #0x1 paciasp For BPF prog, JIT always puts a PACIASP after call site for BTI-enabled kernel, so there is no problem. To fix it, replace BLR with RET to bypass the branch target check.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
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
NVD-CWE-noinfo

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.