{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-21925",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-21925"
  ],
  "published": "2025-04-01T15:40:16Z",
  "summary": "llc: do not use skb_get() before dev_queue_xmit()",
  "details": "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 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]",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.131",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-21925"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cd1c44327bbbd50fc24f2b38892f5f328b784d0f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/13f3f872627f0f27c31245524fc11367756240ad"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9b6f083db141ece0024be01526aa05aa978811cb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/17f86e25431ebc15aa9245ff156414fdad47822d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/416e8b4c20c6398044e93008deefd563289f477d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0f764208dc24ea043c3e20194d32aebf94f8459c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/056e8a46d79e22983bae4267e0d9c52927076f46"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/64e6a754d33d31aa844b3ee66fb93ac84ca1565e"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}