CVE-2025-39995
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-15

Last updated on: 2025-10-29

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: media: i2c: tc358743: Fix use-after-free bugs caused by orphan timer in probe The state->timer is a cyclic timer that schedules work_i2c_poll and delayed_work_enable_hotplug, while rearming itself. Using timer_delete() fails to guarantee the timer isn't still running when destroyed, similarly cancel_delayed_work() cannot ensure delayed_work_enable_hotplug has terminated if already executing. During probe failure after timer initialization, these may continue running as orphans and reference the already-freed tc358743_state object through tc358743_irq_poll_timer. The following is the trace captured by KASAN. BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0 Write of size 8 at addr ffff88800ded83c8 by task swapper/1/0 ... Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_report+0xcf/0x610 ? __pfx_sched_balance_find_src_group+0x10/0x10 ? __run_timer_base.part.0+0x7d7/0x8c0 kasan_report+0xb8/0xf0 ? __run_timer_base.part.0+0x7d7/0x8c0 __run_timer_base.part.0+0x7d7/0x8c0 ? rcu_sched_clock_irq+0xb06/0x27d0 ? __pfx___run_timer_base.part.0+0x10/0x10 ? try_to_wake_up+0xb15/0x1960 ? tmigr_update_events+0x280/0x740 ? _raw_spin_lock_irq+0x80/0xe0 ? __pfx__raw_spin_lock_irq+0x10/0x10 tmigr_handle_remote_up+0x603/0x7e0 ? __pfx_tmigr_handle_remote_up+0x10/0x10 ? sched_balance_trigger+0x98/0x9f0 ? sched_tick+0x221/0x5a0 ? _raw_spin_lock_irq+0x80/0xe0 ? __pfx__raw_spin_lock_irq+0x10/0x10 ? tick_nohz_handler+0x339/0x440 ? __pfx_tmigr_handle_remote_up+0x10/0x10 __walk_groups.isra.0+0x42/0x150 tmigr_handle_remote+0x1f4/0x2e0 ? __pfx_tmigr_handle_remote+0x10/0x10 ? ktime_get+0x60/0x140 ? lapic_next_event+0x11/0x20 ? clockevents_program_event+0x1d4/0x2a0 ? hrtimer_interrupt+0x322/0x780 handle_softirqs+0x16a/0x550 irq_exit_rcu+0xaf/0xe0 sysvec_apic_timer_interrupt+0x70/0x80 </IRQ> ... Allocated by task 141: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x7f/0x90 __kmalloc_node_track_caller_noprof+0x198/0x430 devm_kmalloc+0x7b/0x1e0 tc358743_probe+0xb7/0x610 i2c_device_probe+0x51d/0x880 really_probe+0x1ca/0x5c0 __driver_probe_device+0x248/0x310 driver_probe_device+0x44/0x120 __device_attach_driver+0x174/0x220 bus_for_each_drv+0x100/0x190 __device_attach+0x206/0x370 bus_probe_device+0x123/0x170 device_add+0xd25/0x1470 i2c_new_client_device+0x7a0/0xcd0 do_one_initcall+0x89/0x300 do_init_module+0x29d/0x7f0 load_module+0x4f48/0x69e0 init_module_from_file+0xe4/0x150 idempotent_init_module+0x320/0x670 __x64_sys_finit_module+0xbd/0x120 do_syscall_64+0xac/0x280 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 141: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3a/0x60 __kasan_slab_free+0x3f/0x50 kfree+0x137/0x370 release_nodes+0xa4/0x100 devres_release_group+0x1b2/0x380 i2c_device_probe+0x694/0x880 really_probe+0x1ca/0x5c0 __driver_probe_device+0x248/0x310 driver_probe_device+0x44/0x120 __device_attach_driver+0x174/0x220 bus_for_each_drv+0x100/0x190 __device_attach+0x206/0x370 bus_probe_device+0x123/0x170 device_add+0xd25/0x1470 i2c_new_client_device+0x7a0/0xcd0 do_one_initcall+0x89/0x300 do_init_module+0x29d/0x7f0 load_module+0x4f48/0x69e0 init_module_from_file+0xe4/0x150 idempotent_init_module+0x320/0x670 __x64_sys_finit_module+0xbd/0x120 do_syscall_64+0xac/0x280 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... Replace timer_delete() with timer_delete_sync() and cancel_delayed_work() with cancel_delayed_work_sync() to ensure proper termination of timer and work items before resource cleanup. This bug was initially identified through static analysis. For reproduction and testing, I created a functional emulation of the tc358743 device via a kernel module and introduced faults through the debugfs interface.
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Meta Information
Published
2025-10-15
Last Modified
2025-10-29
Generated
2026-05-07
AI Q&A
2025-10-15
EPSS Evaluated
2026-05-05
NVD
CVE-2025-39995
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free bug in the Linux kernel's media i2c driver for the tc358743 device. It occurs because a cyclic timer and delayed work items continue running after the associated tc358743_state object has been freed during probe failure. The existing functions timer_delete() and cancel_delayed_work() do not guarantee that the timer or work items have fully stopped before the object is freed, leading to references to freed memory and potential kernel crashes or undefined behavior.


How can this vulnerability impact me? :

This vulnerability can cause kernel crashes or instability due to use-after-free memory access. If exploited or triggered, it may lead to denial of service by crashing the system or causing unpredictable kernel behavior, potentially affecting system reliability and availability.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring for use-after-free bugs related to the tc358743 driver in the Linux kernel. Specifically, kernel logs showing KASAN (Kernel Address Sanitizer) reports with messages like 'BUG: KASAN: slab-use-after-free in __run_timer_base.part.0' and call traces involving tc358743_irq_poll_timer indicate the presence of this issue. To detect it, you can check the kernel log using commands such as 'dmesg | grep -i kasan' or 'journalctl -k | grep -i kasan' to find relevant error messages.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed. The fix replaces timer_delete() with timer_delete_sync() and cancel_delayed_work() with cancel_delayed_work_sync() in the tc358743 driver to ensure proper termination of timers and work items before resource cleanup, preventing use-after-free conditions. Until an update is applied, avoid using the affected tc358743 device or module to reduce risk.


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