{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39984","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.150Z","datePublished":"2025-10-15T07:56:03.438Z","dateUpdated":"2026-05-11T21:40:13.408Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T21:40:13.408Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tun: Update napi->skb 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   <TASK>\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   </TASK>\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->skb still point to the original skb, update it after\nXDP process."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tun.c"],"versions":[{"version":"e6d5dbdd20aa6a86974af51deb9414cd2e7794cb","lessThan":"953200d56fc23eebf80a5ad9eed6e2e8a3065093","status":"affected","versionType":"git"},{"version":"e6d5dbdd20aa6a86974af51deb9414cd2e7794cb","lessThan":"1697577e1669b0321d02cd848384a5d33e284296","status":"affected","versionType":"git"},{"version":"e6d5dbdd20aa6a86974af51deb9414cd2e7794cb","lessThan":"1091860a16a86ccdd77c09f2b21a5f634f5ab9ec","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/tun.c"],"versions":[{"version":"6.9","status":"affected"},{"version":"0","lessThan":"6.9","status":"unaffected","versionType":"semver"},{"version":"6.12.50","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.16.10","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.16.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.17"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/953200d56fc23eebf80a5ad9eed6e2e8a3065093"},{"url":"https://git.kernel.org/stable/c/1697577e1669b0321d02cd848384a5d33e284296"},{"url":"https://git.kernel.org/stable/c/1091860a16a86ccdd77c09f2b21a5f634f5ab9ec"}],"title":"net: tun: Update napi->skb after XDP process","x_generator":{"engine":"bippy-1.2.0"}}}}