### [CVE-2025-21925](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21925)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=2.6.12%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

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 devicesnot supporting IFF_TX_SKB_SHARING.In this case, e1000 driver calls eth_skb_pad(), whilethe skb is shared.Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.cNote that e1000 driver might have an issue with pktgen,because it does not clear IFF_TX_SKB_SHARING, this is anorthogonal 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 NOPTICPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0Hardware 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:2178Call 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]

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/ARPSyndicate/cve-scores
- https://github.com/w4zu/Debian_security