{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-39984 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-39984 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-2025-39984 and fix it if it is affected.\n\nWhat it is: CVE-2025-39984 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-2025-39984 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-2025-39984/ (Markdown: https://insights.sbomify.com/CVE-2025-39984/index.md)","id":"CVE-2025-39984","markdown":"https://insights.sbomify.com/CVE-2025-39984/index.md","name":"CVE-2025-39984","record":{"aliases":["BELL-CVE-2025-39984","DEBIAN-CVE-2025-39984","GHSA-3cpf-qphm-hqhv","ROOT-OS-DEBIAN-13-CVE-2025-39984","UBUNTU-CVE-2025-39984"],"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","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel's TUN driver allows local attackers 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\nnet: tun: Update napi-\u003eskb after XDP process\n\nThe syzbot report a UAF issue:\n\n  BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3150 [inline]\n  BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline]\n  BUG: KASAN: slab-use-after-free in napi_gro_frags+0x6e/0x1030 net/core/gro.c:758\n  Read of size 8 at addr ffff88802ef22c18 by task syz.0.17/6079\n  CPU: 0 UID: 0 PID: 6079 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n   print_address_description mm/kasan/report.c:378 [inline]\n   print_report+0xca/0x240 mm/kasan/report.c:482\n   kasan_report+0x118/0x150 mm/kasan/report.c:595\n   skb_reset_mac_header include/linux/skbuff.h:3150 [inline]\n   napi_frags_skb net/core/gro.c:723 [inline]\n   napi_gro_frags+0x6e/0x1030 net/core/gro.c:758\n   tun_get_user+0x28cb/0x3e20 drivers/net/tun.c:1920\n   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996\n   new_sync_write fs/read_write.c:593 [inline]\n   vfs_write+0x5c9/0xb30 fs/read_write.c:686\n   ksys_write+0x145/0x250 fs/read_write.c:738\n   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   \u003c/TASK\u003e\n\n  Allocated by task 6079:\n   kasan_save_stack mm/kasan/common.c:47 [inline]\n   kasan_save_track+0x3e/0x80 mm/kasan/common.c:68\n   unpoison_slab_object mm/kasan/common.c:330 [inline]\n   __kasan_mempool_unpoison_object+0xa0/0x170 mm/kasan/common.c:558\n   kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline]\n   napi_skb_cache_get+0x37b/0x6d0 net/core/skbuff.c:295\n   __alloc_skb+0x11e/0x2d0 net/core/skbuff.c:657\n   napi_alloc_skb+0x84/0x7d0 net/core/skbuff.c:811\n   napi_get_frags+0x69/0x140 net/core/gro.c:673\n   tun_napi_alloc_frags drivers/net/tun.c:1404 [inline]\n   tun_get_user+0x77c/0x3e20 drivers/net/tun.c:1784\n   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996\n   new_sync_write fs/read_write.c:593 [inline]\n   vfs_write+0x5c9/0xb30 fs/read_write.c:686\n   ksys_write+0x145/0x250 fs/read_write.c:738\n   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n  Freed by task 6079:\n   kasan_save_stack mm/kasan/common.c:47 [inline]\n   kasan_save_track+0x3e/0x80 mm/kasan/common.c:68\n   kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576\n   poison_slab_object mm/kasan/common.c:243 [inline]\n   __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275\n   kasan_slab_free include/linux/kasan.h:233 [inline]\n   slab_free_hook mm/slub.c:2422 [inline]\n   slab_free mm/slub.c:4695 [inline]\n   kmem_cache_free+0x18f/0x400 mm/slub.c:4797\n   skb_pp_cow_data+0xdd8/0x13e0 net/core/skbuff.c:969\n   netif_skb_check_for_xdp net/core/dev.c:5390 [inline]\n   netif_receive_generic_xdp net/core/dev.c:5431 [inline]\n   do_xdp_generic+0x699/0x11a0 net/core/dev.c:5499\n   tun_get_user+0x2523/0x3e20 drivers/net/tun.c:1872\n   tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996\n   new_sync_write fs/read_write.c:593 [inline]\n   vfs_write+0x5c9/0xb30 fs/read_write.c:686\n   ksys_write+0x145/0x250 fs/read_write.c:738\n   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nAfter commit e6d5dbdd20aa (\"xdp: add multi-buff support for xdp running in\ngeneric mode\"), the original skb may be freed in skb_pp_cow_data() when\nXDP program was attached, which was allocated in tun_napi_alloc_frags().\nHowever, the napi-\u003eskb still point to the original skb, update it after\nXDP process.","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":"net: tun: Update napi-\u003eskb after XDP process","id":"CVE-2025-39984","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow","id":"CVE-2025-39985"},"packages":[],"prev":{"headline":"Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue","id":"CVE-2025-39983"},"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 vulnerability in the Linux kernel's TUN driver allows local attackers to execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2025-39984/"}