GHSA-47J5-HMHQ-4C74

Vulnerability from github – Published: 2026-04-13 15:31 – Updated: 2026-08-23 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

net: bonding: fix use-after-free in bond_xmit_broadcast()

bond_xmit_broadcast() reuses the original skb for the last slave (determined by bond_is_last_slave()) and clones it for others. Concurrent slave enslave/release can mutate the slave list during RCU-protected iteration, changing which slave is "last" mid-loop. This causes the original skb to be double-consumed (double-freed).

Replace the racy bond_is_last_slave() check with a simple index comparison (i + 1 == slaves_count) against the pre-snapshot slave count taken via READ_ONCE() before the loop. This preserves the zero-copy optimization for the last slave while making the "last" determination stable against concurrent list mutations.

The UAF can trigger the following crash:

================================================================== BUG: KASAN: slab-use-after-free in skb_clone Read of size 8 at addr ffff888100ef8d40 by task exploit/147

CPU: 1 UID: 0 PID: 147 Comm: exploit Not tainted 7.0.0-rc3+ #4 PREEMPTLAZY Call Trace: dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:597) skb_clone (include/linux/skbuff.h:1724 include/linux/skbuff.h:1792 include/linux/skbuff.h:3396 net/core/skbuff.c:2108) bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5334) bond_start_xmit (drivers/net/bonding/bond_main.c:5567 drivers/net/bonding/bond_main.c:5593) dev_hard_start_xmit (include/linux/netdevice.h:5325 include/linux/netdevice.h:5334 net/core/dev.c:3871 net/core/dev.c:3887) __dev_queue_xmit (include/linux/netdevice.h:3601 net/core/dev.c:4838) ip6_finish_output2 (include/net/neighbour.h:540 include/net/neighbour.h:554 net/ipv6/ip6_output.c:136) ip6_finish_output (net/ipv6/ip6_output.c:208 net/ipv6/ip6_output.c:219) ip6_output (net/ipv6/ip6_output.c:250) ip6_send_skb (net/ipv6/ip6_output.c:1985) udp_v6_send_skb (net/ipv6/udp.c:1442) udpv6_sendmsg (net/ipv6/udp.c:1733) __sys_sendto (net/socket.c:730 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Allocated by task 147:

Freed by task 147:

The buggy address belongs to the object at ffff888100ef8c80 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 192 bytes inside of freed 224-byte region [ffff888100ef8c80, ffff888100ef8d60)

Memory state around the buggy address: ffff888100ef8c00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff888100ef8c80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff888100ef8d00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888100ef8d80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888100ef8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-31419"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-13T14:16:11Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bonding: fix use-after-free in bond_xmit_broadcast()\n\nbond_xmit_broadcast() reuses the original skb for the last slave\n(determined by bond_is_last_slave()) and clones it for others.\nConcurrent slave enslave/release can mutate the slave list during\nRCU-protected iteration, changing which slave is \"last\" mid-loop.\nThis causes the original skb to be double-consumed (double-freed).\n\nReplace the racy bond_is_last_slave() check with a simple index\ncomparison (i + 1 == slaves_count) against the pre-snapshot slave\ncount taken via READ_ONCE() before the loop.  This preserves the\nzero-copy optimization for the last slave while making the \"last\"\ndetermination stable against concurrent list mutations.\n\nThe UAF can trigger the following crash:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in skb_clone\nRead of size 8 at addr ffff888100ef8d40 by task exploit/147\n\nCPU: 1 UID: 0 PID: 147 Comm: exploit Not tainted 7.0.0-rc3+ #4 PREEMPTLAZY\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl (lib/dump_stack.c:123)\n print_report (mm/kasan/report.c:379 mm/kasan/report.c:482)\n kasan_report (mm/kasan/report.c:597)\n skb_clone (include/linux/skbuff.h:1724 include/linux/skbuff.h:1792 include/linux/skbuff.h:3396 net/core/skbuff.c:2108)\n bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5334)\n bond_start_xmit (drivers/net/bonding/bond_main.c:5567 drivers/net/bonding/bond_main.c:5593)\n dev_hard_start_xmit (include/linux/netdevice.h:5325 include/linux/netdevice.h:5334 net/core/dev.c:3871 net/core/dev.c:3887)\n __dev_queue_xmit (include/linux/netdevice.h:3601 net/core/dev.c:4838)\n ip6_finish_output2 (include/net/neighbour.h:540 include/net/neighbour.h:554 net/ipv6/ip6_output.c:136)\n ip6_finish_output (net/ipv6/ip6_output.c:208 net/ipv6/ip6_output.c:219)\n ip6_output (net/ipv6/ip6_output.c:250)\n ip6_send_skb (net/ipv6/ip6_output.c:1985)\n udp_v6_send_skb (net/ipv6/udp.c:1442)\n udpv6_sendmsg (net/ipv6/udp.c:1733)\n __sys_sendto (net/socket.c:730 net/socket.c:742 net/socket.c:2206)\n __x64_sys_sendto (net/socket.c:2209)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n \u003c/TASK\u003e\n\nAllocated by task 147:\n\nFreed by task 147:\n\nThe buggy address belongs to the object at ffff888100ef8c80\n which belongs to the cache skbuff_head_cache of size 224\nThe buggy address is located 192 bytes inside of\n freed 224-byte region [ffff888100ef8c80, ffff888100ef8d60)\n\nMemory state around the buggy address:\n ffff888100ef8c00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc\n ffff888100ef8c80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\u003effff888100ef8d00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc\n                                                    ^\n ffff888100ef8d80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb\n ffff888100ef8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n==================================================================",
  "id": "GHSA-47j5-hmhq-4c74",
  "modified": "2026-08-23T15:32:54Z",
  "published": "2026-04-13T15:31:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31419"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31419.json"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5b94654a4a19891a8108d66ef166de6c028c6cd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d4cc7e4c80b1634c7b1497574a2fdb18df6c026c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a0f661918edc79d7a75e468128af8d41e2a1a83a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3453882f36c40d2339267093676585a89808a73d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2de5c8eea0a9db99dae7c36f4b541b74b41d3a04"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2884bf72fb8f03409e423397319205de48adca16"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/00752893f96b344f258c9c6de18b33171ac4872c"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2457829"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-31419"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36534"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36533"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36532"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36531"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36530"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:36172"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:35870"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:27354"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:27353"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25217"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:25191"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:23224"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:22940"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:22900"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:22334"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:21209"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:19521"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:13566"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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