UBUNTU-CVE-2025-21925
In the Linux kernel, the following vulnerability has been resolved: llc: do not use skb_get() before dev_queue_xmit() syzbot is able to crash hosts [1], using llc and devices not supporting IFF_TX_SKB_SHARING. In this case, e1000 driver calls eth_skb_pad(), while the skb is shared. Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c Note that e1000 driver might have an issue with pktgen, because it does not clear IFF_TX_SKB_SHARING, this is an orthogonal change. We need to audit other skb_get() uses in net/llc. [1] kernel BUG at net/core/skbuff.c:2178 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178 Call Trace: <TASK> __skb_pad+0x18a/0x610 net/core/skbuff.c:2466 __skb_put_padto include/linux/skbuff.h:3843 [inline] skb_put_padto include/linux/skbuff.h:3862 [inline] eth_skb_pad include/linux/etherdevice.h:656 [inline] e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4045 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621 dev_queue_xmit include/linux/netdevice.h:3313 [inline] llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209 llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993 sock_sendmsg_nosec net/socket.c:718 [inline]
02 / AFFECTED SOFTWARE
Affected packages
31 explicit affected versions
106 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
5 explicit affected versions
45 explicit affected versions
26 explicit affected versions
11 explicit affected versions
39 explicit affected versions
63 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
73 explicit affected versions
24 explicit affected versions
58 explicit affected versions
23 explicit affected versions
76 explicit affected versions
66 explicit affected versions
59 explicit affected versions
10 explicit affected versions
21 explicit affected versions
26 explicit affected versions
65 explicit affected versions
191 explicit affected versions
7 explicit affected versions
64 explicit affected versions
26 explicit affected versions
104 explicit affected versions
13 explicit affected versions
85 explicit affected versions
28 explicit affected versions
35 explicit affected versions
25 explicit affected versions
18 explicit affected versions
24 explicit affected versions
118 explicit affected versions
64 explicit affected versions
13 explicit affected versions
4 explicit affected versions
121 explicit affected versions
23 explicit affected versions
36 explicit affected versions
60 explicit affected versions
32 explicit affected versions
6 explicit affected versions
7 explicit affected versions
12 explicit affected versions
111 explicit affected versions
6 explicit affected versions
56 explicit affected versions
12 explicit affected versions
14 explicit affected versions
1 explicit affected versions
7 explicit affected versions
4 explicit affected versions
93 explicit affected versions
12 explicit affected versions
109 explicit affected versions
117 explicit affected versions
12 explicit affected versions
25 explicit affected versions
104 explicit affected versions
120 explicit affected versions
19 explicit affected versions
19 explicit affected versions
18 explicit affected versions
10 explicit affected versions
37 explicit affected versions
6 explicit affected versions
13 explicit affected versions
24 explicit affected versions
10 explicit affected versions
40 explicit affected versions
1 explicit affected versions
26 explicit affected versions
1 explicit affected versions
13 explicit affected versions
144 explicit affected versions
14 explicit affected versions
1 explicit affected versions
29 explicit affected versions
96 explicit affected versions
13 explicit affected versions
3 explicit affected versions
70 explicit affected versions
25 explicit affected versions
25 explicit affected versions
1 explicit affected versions
10 explicit affected versions
87 explicit affected versions
65 explicit affected versions
108 explicit affected versions
28 explicit affected versions
64 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
4 explicit affected versions
188 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
107 explicit affected versions
138 explicit affected versions
2 explicit affected versions
56 explicit affected versions
5 explicit affected versions
50 explicit affected versions
132 explicit affected versions
66 explicit affected versions
165 explicit affected versions
154 explicit affected versions
26 explicit affected versions
26 explicit affected versions
41 explicit affected versions
1 explicit affected versions
20 explicit affected versions
31 explicit affected versions
13 explicit affected versions
30 explicit affected versions
139 explicit affected versions
13 explicit affected versions
16 explicit affected versions
67 explicit affected versions
34 explicit affected versions
54 explicit affected versions
27 explicit affected versions
116 explicit affected versions
3 explicit affected versions
93 explicit affected versions
1 explicit affected versions
5 explicit affected versions
8 explicit affected versions
2 explicit affected versions
74 explicit affected versions
51 explicit affected versions
92 explicit affected versions
30 explicit affected versions
15 explicit affected versions
26 explicit affected versions
12 explicit affected versions
53 explicit affected versions
27 explicit affected versions
40 explicit affected versions
1 explicit affected versions
1 explicit affected versions
98 explicit affected versions
3 explicit affected versions
8 explicit affected versions
1 explicit affected versions
10 explicit affected versions
5 explicit affected versions
30 explicit affected versions
96 explicit affected versions
13 explicit affected versions
59 explicit affected versions
7 explicit affected versions
140 explicit affected versions
94 explicit affected versions
57 explicit affected versions
10 explicit affected versions
12 explicit affected versions
15 explicit affected versions
94 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
45 explicit affected versions
37 explicit affected versions
35 explicit affected versions
14 explicit affected versions
38 explicit affected versions
167 explicit affected versions
9 explicit affected versions
55 explicit affected versions
11 explicit affected versions
24 explicit affected versions
8 explicit affected versions
66 explicit affected versions
7 explicit affected versions
35 explicit affected versions
97 explicit affected versions
67 explicit affected versions
121 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
64 explicit affected versions
56 explicit affected versions
13 explicit affected versions
43 explicit affected versions
62 explicit affected versions
10 explicit affected versions
8 explicit affected versions
29 explicit affected versions
14 explicit affected versions
92 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
69 explicit affected versions
3 explicit affected versions
23 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: llc: do not use skb_get() before dev_queue_xmit() syzbot is able to crash hosts [1], using llc and devices not supporting IFF_TX_SKB_SHARING. In this case, e1000 driver calls eth_skb_pad(), while the skb is shared. Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c Note that e1000 driver might have an issue with pktgen, because it does not clear IFF_TX_SKB_SHARING, this is an orthogonal change. We need to audit other skb_get() uses in net/llc. [1] kernel BUG at net/core/skbuff.c:2178 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178 Call Trace: <TASK> __skb_pad+0x18a/0x610 net/core/skbuff.c:2466 __skb_put_padto include/linux/skbuff.h:3843 [inline] skb_put_padto include/linux/skbuff.h:3862 [inline] eth_skb_pad include/linux/etherdevice.h:656 [inline] e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4045 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621 dev_queue_xmit include/linux/netdevice.h:3313 [inline] llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209 llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993 sock_sendmsg_nosec net/socket.c:718 [inline]
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/64e6a754d33d31aa844b3ee66fb93ac84ca1565e
- https://git.kernel.org/stable/c/056e8a46d79e22983bae4267e0d9c52927076f46
- https://git.kernel.org/stable/c/0f764208dc24ea043c3e20194d32aebf94f8459c
- https://git.kernel.org/stable/c/13f3f872627f0f27c31245524fc11367756240ad
- https://git.kernel.org/stable/c/17f86e25431ebc15aa9245ff156414fdad47822d
- https://git.kernel.org/stable/c/416e8b4c20c6398044e93008deefd563289f477d
- https://git.kernel.org/stable/c/64e6a754d33d31aa844b3ee66fb93ac84ca1565e
- https://git.kernel.org/stable/c/9b6f083db141ece0024be01526aa05aa978811cb
- https://git.kernel.org/stable/c/cd1c44327bbbd50fc24f2b38892f5f328b784d0f
- https://ubuntu.com/security/CVE-2025-21925
- https://ubuntu.com/security/notices/USN-7510-1
- https://ubuntu.com/security/notices/USN-7510-2
- https://ubuntu.com/security/notices/USN-7510-3
- https://ubuntu.com/security/notices/USN-7510-4
- https://ubuntu.com/security/notices/USN-7510-5
- https://ubuntu.com/security/notices/USN-7510-6
- https://ubuntu.com/security/notices/USN-7510-7
- https://ubuntu.com/security/notices/USN-7510-8
- https://ubuntu.com/security/notices/USN-7511-1
- https://ubuntu.com/security/notices/USN-7511-2
- https://ubuntu.com/security/notices/USN-7511-3
- https://ubuntu.com/security/notices/USN-7512-1
- https://ubuntu.com/security/notices/USN-7516-1
- https://ubuntu.com/security/notices/USN-7516-2
- https://ubuntu.com/security/notices/USN-7516-3
- https://ubuntu.com/security/notices/USN-7516-4
- https://ubuntu.com/security/notices/USN-7516-5
- https://ubuntu.com/security/notices/USN-7516-6
- https://ubuntu.com/security/notices/USN-7516-7
- https://ubuntu.com/security/notices/USN-7516-8
- https://ubuntu.com/security/notices/USN-7516-9
- https://ubuntu.com/security/notices/USN-7517-1
- https://ubuntu.com/security/notices/USN-7517-2
- https://ubuntu.com/security/notices/USN-7517-3
- https://ubuntu.com/security/notices/USN-7518-1
- https://ubuntu.com/security/notices/USN-7539-1
- https://ubuntu.com/security/notices/USN-7540-1
- https://ubuntu.com/security/notices/USN-7593-1
- https://ubuntu.com/security/notices/USN-7602-1
- https://ubuntu.com/security/notices/USN-7605-1
- https://ubuntu.com/security/notices/USN-7605-2
- https://ubuntu.com/security/notices/USN-7606-1
- https://ubuntu.com/security/notices/USN-7628-1
- https://ubuntu.com/security/notices/USN-7640-1
- https://ubuntu.com/security/notices/USN-7764-1
- https://ubuntu.com/security/notices/USN-7764-2
- https://ubuntu.com/security/notices/USN-7765-1
- https://ubuntu.com/security/notices/USN-7766-1
- https://ubuntu.com/security/notices/USN-7767-1
- https://ubuntu.com/security/notices/USN-7767-2
- https://ubuntu.com/security/notices/USN-7779-1
- https://ubuntu.com/security/notices/USN-7790-1
- https://ubuntu.com/security/notices/USN-7800-1
- https://ubuntu.com/security/notices/USN-7801-1
- https://ubuntu.com/security/notices/USN-7801-2
- https://ubuntu.com/security/notices/USN-7801-3
- https://ubuntu.com/security/notices/USN-7802-1
- https://ubuntu.com/security/notices/USN-7809-1
- https://www.cve.org/CVERecord?id=CVE-2025-21925