In the Linux kernel, the following vulnerability has been resolved:
net: tun: Update napi->skb after XDP process
The syzbot report a UAF issue:
BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline]
BUG: KASAN: slab-use-after-free in napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
Read of size 8 at addr ffff88802ef22c18 by task syz.0.17/6079
CPU: 0 UID: 0 PID: 6079 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
napi_frags_skb net/core/gro.c:723 [inline]
napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
tun_get_user+0x28cb/0x3e20 drivers/net/tun.c:1920
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 6079:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_mempool_unpoison_object+0xa0/0x170 mm/kasan/common.c:558
kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline]
napi_skb_cache_get+0x37b/0x6d0 net/core/skbuff.c:295
__alloc_skb+0x11e/0x2d0 net/core/skbuff.c:657
napi_alloc_skb+0x84/0x7d0 net/core/skbuff.c:811
napi_get_frags+0x69/0x140 net/core/gro.c:673
tun_napi_alloc_frags drivers/net/tun.c:1404 [inline]
tun_get_user+0x77c/0x3e20 drivers/net/tun.c:1784
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6079:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:243 [inline]
__kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2422 [inline]
slab_free mm/slub.c:4695 [inline]
kmem_cache_free+0x18f/0x400 mm/slub.c:4797
skb_pp_cow_data+0xdd8/0x13e0 net/core/skbuff.c:969
netif_skb_check_for_xdp net/core/dev.c:5390 [inline]
netif_receive_generic_xdp net/core/dev.c:5431 [inline]
do_xdp_generic+0x699/0x11a0 net/core/dev.c:5499
tun_get_user+0x2523/0x3e20 drivers/net/tun.c:1872
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
After commit e6d5dbdd20aa ("xdp: add multi-buff support for xdp running in
generic mode"), the original skb may be freed in skb_pp_cow_data() when
XDP program was attached, which was allocated in tun_napi_alloc_frags().
However, the napi->skb still point to the original skb, update it after
XDP process.
net: tun: Update napi->skb after XDP process
The syzbot report a UAF issue:
BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline]
BUG: KASAN: slab-use-after-free in napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
Read of size 8 at addr ffff88802ef22c18 by task syz.0.17/6079
CPU: 0 UID: 0 PID: 6079 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
skb_reset_mac_header include/linux/skbuff.h:3150 [inline]
napi_frags_skb net/core/gro.c:723 [inline]
napi_gro_frags+0x6e/0x1030 net/core/gro.c:758
tun_get_user+0x28cb/0x3e20 drivers/net/tun.c:1920
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Allocated by task 6079:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_mempool_unpoison_object+0xa0/0x170 mm/kasan/common.c:558
kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline]
napi_skb_cache_get+0x37b/0x6d0 net/core/skbuff.c:295
__alloc_skb+0x11e/0x2d0 net/core/skbuff.c:657
napi_alloc_skb+0x84/0x7d0 net/core/skbuff.c:811
napi_get_frags+0x69/0x140 net/core/gro.c:673
tun_napi_alloc_frags drivers/net/tun.c:1404 [inline]
tun_get_user+0x77c/0x3e20 drivers/net/tun.c:1784
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6079:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:243 [inline]
__kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2422 [inline]
slab_free mm/slub.c:4695 [inline]
kmem_cache_free+0x18f/0x400 mm/slub.c:4797
skb_pp_cow_data+0xdd8/0x13e0 net/core/skbuff.c:969
netif_skb_check_for_xdp net/core/dev.c:5390 [inline]
netif_receive_generic_xdp net/core/dev.c:5431 [inline]
do_xdp_generic+0x699/0x11a0 net/core/dev.c:5499
tun_get_user+0x2523/0x3e20 drivers/net/tun.c:1872
tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
After commit e6d5dbdd20aa ("xdp: add multi-buff support for xdp running in
generic mode"), the original skb may be freed in skb_pp_cow_data() when
XDP program was attached, which was allocated in tun_napi_alloc_frags().
However, the napi->skb still point to the original skb, update it after
XDP process.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
No data.
No data.
OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.
| Vendors | Products |
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Linux
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Linux Kernel
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Advisories
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Fixes
Solution
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Workaround
No workaround given by the vendor.
References
History
Mon, 20 Oct 2025 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Thu, 16 Oct 2025 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Wed, 15 Oct 2025 08:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net: tun: Update napi->skb after XDP process The syzbot report a UAF issue: BUG: KASAN: slab-use-after-free in skb_reset_mac_header include/linux/skbuff.h:3150 [inline] BUG: KASAN: slab-use-after-free in napi_frags_skb net/core/gro.c:723 [inline] BUG: KASAN: slab-use-after-free in napi_gro_frags+0x6e/0x1030 net/core/gro.c:758 Read of size 8 at addr ffff88802ef22c18 by task syz.0.17/6079 CPU: 0 UID: 0 PID: 6079 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 skb_reset_mac_header include/linux/skbuff.h:3150 [inline] napi_frags_skb net/core/gro.c:723 [inline] napi_gro_frags+0x6e/0x1030 net/core/gro.c:758 tun_get_user+0x28cb/0x3e20 drivers/net/tun.c:1920 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Allocated by task 6079: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_mempool_unpoison_object+0xa0/0x170 mm/kasan/common.c:558 kasan_mempool_unpoison_object include/linux/kasan.h:388 [inline] napi_skb_cache_get+0x37b/0x6d0 net/core/skbuff.c:295 __alloc_skb+0x11e/0x2d0 net/core/skbuff.c:657 napi_alloc_skb+0x84/0x7d0 net/core/skbuff.c:811 napi_get_frags+0x69/0x140 net/core/gro.c:673 tun_napi_alloc_frags drivers/net/tun.c:1404 [inline] tun_get_user+0x77c/0x3e20 drivers/net/tun.c:1784 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6079: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4797 skb_pp_cow_data+0xdd8/0x13e0 net/core/skbuff.c:969 netif_skb_check_for_xdp net/core/dev.c:5390 [inline] netif_receive_generic_xdp net/core/dev.c:5431 [inline] do_xdp_generic+0x699/0x11a0 net/core/dev.c:5499 tun_get_user+0x2523/0x3e20 drivers/net/tun.c:1872 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1996 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f After commit e6d5dbdd20aa ("xdp: add multi-buff support for xdp running in generic mode"), the original skb may be freed in skb_pp_cow_data() when XDP program was attached, which was allocated in tun_napi_alloc_frags(). However, the napi->skb still point to the original skb, update it after XDP process. | |
| Title | net: tun: Update napi->skb after XDP process | |
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-15T07:56:03.438Z
Reserved: 2025-04-16T07:20:57.150Z
Link: CVE-2025-39984
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2025-10-15T08:15:36.400
Modified: 2025-10-16T15:29:11.563
Link: CVE-2025-39984
Redhat
OpenCVE Enrichment
Updated: 2025-10-20T13:26:51Z
Weaknesses
No weakness.