{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-39996 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-39996 is an use after free vulnerability in Linux, published on 15 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-39996 and fix it if it is affected.\n\nWhat it is: CVE-2025-39996 is an use after free vulnerability in Linux, published on 15 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-39996 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-39996/ (Markdown: https://insights.sbomify.com/CVE-2025-39996/index.md)","id":"CVE-2025-39996","markdown":"https://insights.sbomify.com/CVE-2025-39996/index.md","name":"CVE-2025-39996","record":{"aliases":["BELL-CVE-2025-39996","DEBIAN-CVE-2025-39996","GHSA-g9x2-qjcj-fqr4","ROOT-OS-DEBIAN-11-CVE-2025-39996","ROOT-OS-DEBIAN-12-CVE-2025-39996","ROOT-OS-DEBIAN-13-CVE-2025-39996","ROOT-OS-UBUNTU-2204-CVE-2025-39996","ROOT-OS-UBUNTU-2404-CVE-2025-39996","UBUNTU-CVE-2025-39996"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel driver","requires_auth":"high_privilege","summary":"A use-after-free in the Linux kernel's b2c2 flexcop PCI driver allows local attackers with high privileges to execute arbitrary code or escalate privileges.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove\n\nThe original code uses cancel_delayed_work() in flexcop_pci_remove(), which\ndoes not guarantee that the delayed work item irq_check_work has fully\ncompleted if it was already running. This leads to use-after-free scenarios\nwhere flexcop_pci_remove() may free the flexcop_device while irq_check_work\nis still active and attempts to dereference the device.\n\nA typical race condition is illustrated below:\n\nCPU 0 (remove)                         | CPU 1 (delayed work callback)\nflexcop_pci_remove()                   | flexcop_pci_irq_check_work()\n  cancel_delayed_work()                |\n  flexcop_device_kfree(fc_pci-\u003efc_dev) |\n                                       |   fc = fc_pci-\u003efc_dev; // UAF\n\nThis is confirmed by a KASAN report:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0\nWrite of size 8 at addr ffff8880093aa8c8 by task bash/135\n...\nCall Trace:\n \u003cIRQ\u003e\n dump_stack_lvl+0x55/0x70\n print_report+0xcf/0x610\n ? __run_timer_base.part.0+0x7d7/0x8c0\n kasan_report+0xb8/0xf0\n ? __run_timer_base.part.0+0x7d7/0x8c0\n __run_timer_base.part.0+0x7d7/0x8c0\n ? __pfx___run_timer_base.part.0+0x10/0x10\n ? __pfx_read_tsc+0x10/0x10\n ? ktime_get+0x60/0x140\n ? lapic_next_event+0x11/0x20\n ? clockevents_program_event+0x1d4/0x2a0\n run_timer_softirq+0xd1/0x190\n handle_softirqs+0x16a/0x550\n irq_exit_rcu+0xaf/0xe0\n sysvec_apic_timer_interrupt+0x70/0x80\n \u003c/IRQ\u003e\n...\n\nAllocated by task 1:\n kasan_save_stack+0x24/0x50\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0x7f/0x90\n __kmalloc_noprof+0x1be/0x460\n flexcop_device_kmalloc+0x54/0xe0\n flexcop_pci_probe+0x1f/0x9d0\n local_pci_probe+0xdc/0x190\n pci_device_probe+0x2fe/0x470\n really_probe+0x1ca/0x5c0\n __driver_probe_device+0x248/0x310\n driver_probe_device+0x44/0x120\n __driver_attach+0xd2/0x310\n bus_for_each_dev+0xed/0x170\n bus_add_driver+0x208/0x500\n driver_register+0x132/0x460\n do_one_initcall+0x89/0x300\n kernel_init_freeable+0x40d/0x720\n kernel_init+0x1a/0x150\n ret_from_fork+0x10c/0x1a0\n ret_from_fork_asm+0x1a/0x30\n\nFreed by task 135:\n kasan_save_stack+0x24/0x50\n kasan_save_track+0x14/0x30\n kasan_save_free_info+0x3a/0x60\n __kasan_slab_free+0x3f/0x50\n kfree+0x137/0x370\n flexcop_device_kfree+0x32/0x50\n pci_device_remove+0xa6/0x1d0\n device_release_driver_internal+0xf8/0x210\n pci_stop_bus_device+0x105/0x150\n pci_stop_and_remove_bus_device_locked+0x15/0x30\n remove_store+0xcc/0xe0\n kernfs_fop_write_iter+0x2c3/0x440\n vfs_write+0x871/0xd70\n ksys_write+0xee/0x1c0\n do_syscall_64+0xac/0x280\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n...\n\nReplace cancel_delayed_work() with cancel_delayed_work_sync() to ensure\nthat the delayed work item is properly canceled and any executing delayed\nwork has finished before the device memory is deallocated.\n\nThis bug was initially identified through static analysis. To reproduce\nand test it, I simulated the B2C2 FlexCop PCI device in QEMU and introduced\nartificial delays within the flexcop_pci_irq_check_work() function to\nincrease the likelihood of triggering the bug.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove","id":"CVE-2025-39996","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2025"},"n_packages":0,"n_references":9,"next":{"headline":"ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free","id":"CVE-2025-39997"},"packages":[],"prev":{"headline":"media: i2c: tc358743: Fix use-after-free bugs caused by orphan timer in probe","id":"CVE-2025-39995"},"products":["Linux"],"published":"2025-10-15","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel's b2c2 flexcop PCI driver allows local attackers with high privileges to execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2025-39996/"}