{"id":"CVE-2025-21925","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nllc: do not use skb_get() before dev_queue_xmit()\n\nsyzbot is able to crash hosts [1], using llc and devices\nnot supporting IFF_TX_SKB_SHARING.\n\nIn this case, e1000 driv…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nllc: do not use skb_get() before dev_queue_xmit()\n\nsyzbot is able to crash hosts [1], using llc and devices\nnot supporting IFF_TX_SKB_SHARING.\n\nIn this case, e1000 driv…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.13, < 5.4.291","linux_kernel >= 5.5, < 5.10.235","linux_kernel >= 5.11, < 5.15.179","linux_kernel >= 5.16, < 6.1.131","linux_kernel >= 6.2, < 6.6.83","linux_kernel >= 6.7, < 6.12.19","linux_kernel >= 6.13, < 6.13.7","linux_kernel = 2.6.12","linux_kernel = 6.14"],"patched":["linux_kernel 6.13.7"],"published":"2025-04-01","updated":"2026-07-14","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21925","references":[{"url":"https://git.kernel.org/stable/c/056e8a46d79e22983bae4267e0d9c52927076f46","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0f764208dc24ea043c3e20194d32aebf94f8459c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/13f3f872627f0f27c31245524fc11367756240ad","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/17f86e25431ebc15aa9245ff156414fdad47822d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/416e8b4c20c6398044e93008deefd563289f477d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/64e6a754d33d31aa844b3ee66fb93ac84ca1565e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9b6f083db141ece0024be01526aa05aa978811cb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cd1c44327bbbd50fc24f2b38892f5f328b784d0f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00222,"epssPercentile":0.13106,"ingestedAt":"2026-07-14T13:36:56.071Z","slug":"CVE-2025-21925","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nllc: do not use skb_get() before dev_queue_xmit()\n\nsyzbot is able to crash hosts [1], using llc and devices\nnot supporting IFF_TX_SKB_SHARING.\n\nIn this case, e1000 driver calls eth_skb_pad(), while\nthe skb is shared.\n\nSimply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c\n\nNote that e1000 driver might have an issue with pktgen,\nbecause it does not clear IFF_TX_SKB_SHARING, this is an\northogonal change.\n\nWe need to audit other skb_get() uses in net/llc.\n\n[1]\n\nkernel BUG at net/core/skbuff.c:2178 !\nOops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\n RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178\nCall Trace:\n <TASK>\n  __skb_pad+0x18a/0x610 net/core/skbuff.c:2466\n  __skb_put_padto include/linux/skbuff.h:3843 [inline]\n  skb_put_padto include/linux/skbuff.h:3862 [inline]\n  eth_skb_pad include/linux/etherdevice.h:656 [inline]\n  e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128\n  __netdev_start_xmit include/linux/netdevice.h:5151 [inline]\n  netdev_start_xmit include/linux/netdevice.h:5160 [inline]\n  xmit_one net/core/dev.c:3806 [inline]\n  dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822\n  sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343\n  __dev_xmit_skb net/core/dev.c:4045 [inline]\n  __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621\n  dev_queue_xmit include/linux/netdevice.h:3313 [inline]\n  llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144\n  llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline]\n  llc_sap_next_state net/llc/llc_sap.c:182 [inline]\n  llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209\n  llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993\n  sock_sendmsg_nosec net/socket.c:718 [inline]\n\n## Affected\n\n- `linux_kernel >= 2.6.13, < 5.4.291`\n- `linux_kernel >= 5.5, < 5.10.235`\n- `linux_kernel >= 5.11, < 5.15.179`\n- `linux_kernel >= 5.16, < 6.1.131`\n- `linux_kernel >= 6.2, < 6.6.83`\n- `linux_kernel >= 6.7, < 6.12.19`\n- `linux_kernel >= 6.13, < 6.13.7`\n- `linux_kernel = 2.6.12`\n- `linux_kernel = 6.14`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.13.7`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}