CVE-2025-39996 — media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove

Affected: Linux

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

media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove

The original code uses cancel_delayed_work() in flexcop_pci_remove(), which does not guarantee that the delayed work item irq_check_work has fully completed if it was already running. This leads to use-after-free scenarios where flexcop_pci_remove() may free the flexcop_device while irq_check_work is still active and attempts to dereference the device.

A typical race condition is illustrated below:

This is confirmed by a KASAN report:

================================================================== BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0 Write of size 8 at addr ffff8880093aa8c8 by task bash/135 ... Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_report+0xcf/0x610 ? __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 ? __pfx___run_timer_base.part.0+0x10/0x10 ? __pfx_read_tsc+0x10/0x10 ? ktime_get+0x60/0x140 ? lapic_next_event+0x11/0x20 ? clockevents_program_event+0x1d4/0x2a0 run_timer_softirq+0xd1/0x190 handle…

USN-8033-1 — linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-lowlatency, linux…

Affected: Ubuntu:Pro:20.04:LTS: linux-hwe-5.15, Ubuntu:Pro:20.04:LTS: linux-ibm-5.15, Ubuntu:Pro:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-aws, Ubuntu:22.04:LTS: linux-gcp, Ubuntu:22.04:LTS: linux-gke, Ubuntu:22.04:LTS: linux-gkeop, Ubuntu:22.04:LTS: linux-ibm, Ubuntu:22.04:LTS: linux-lowlatency

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: - Nios II architecture; - Sun Sparc architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Drivers core; - Bus devices; - Hardware random number generator core; - Data acquisition framework and drivers; - CPU frequency scaling framework; - DMA engine subsystem; - GPU drivers; - HW tracing; - Input Device (Miscellaneous) drivers; - Multiple devices driver; - Media drivers; - MOST (Media Oriented Systems Transport) drivers; - MTD block device drivers; - Network drivers; - NVME drivers; - PCI subsystem; - Performance monitor drivers; - Pin controllers subsystem; - x86 platform drivers; - PPS (Pulse Per Second) driver; - PWM drivers; - SCSI subsystem; - TCM subsystem; - Userspace I/O drivers; - USB Gadget drivers; - USB Host Controller drivers; - Framebuffer layer; - BTRFS file system; - File systems infrastructure; - Ext4 file system; - Network file system (NFS) server daemon; - NTFS3 file system; - SMB network file system; - padata parallel execution mechanism; - IP tunnels definitions; - Network sockets; - XFRM subsystem; - Control group (cgroup); - Padata parallel execution mechanism; - PID allocator; - Tracing infrastructure; - Memory management; - 9…

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CVE-2025-39996 — media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove

USN-8033-1 — linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-lowlatency, linux…