net: bonding: fix use-after-free in bond_xmit_broadcast()_CVE-2026-31419

{
    "lastseen": "",
    "description": "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 <TASK>\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 </TASK>\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>ffff888100ef8d00: 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==================================================================",
    "published": "2026-04-13T13:40:23.279Z",
    "modified": "2026-04-27T14:03:01.326Z",
    "type": "cve",
    "title": "net: bonding: fix use-after-free in bond_xmit_broadcast()",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/d4cc7e4c80b1634c7b1497574a2fdb18df6c026c\nhttps://git.kernel.org/stable/c/f5b94654a4a19891a8108d66ef166de6c028c6cd\nhttps://git.kernel.org/stable/c/2884bf72fb8f03409e423397319205de48adca16",
    "id": "CVE-2026-31419",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 4e5bd03ae34652cd932ab4c91c71c511793df75c\nLinux Linux 4e5bd03ae34652cd932ab4c91c71c511793df75c\nLinux Linux 4e5bd03ae34652cd932ab4c91c71c511793df75c\nLinux Linux 20949c3816463e97c6f8fe84c0280c7e5ae83a8d\nLinux Linux f1d206181f19b00b275b258fea1418718a2f4173\nLinux Linux c1f1691ef84fa6d38fa5e5148eca073145e97ffa\nLinux Linux 5.17",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
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        "baseScore": 0,
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        "cvssV3": {
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    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "4e5bd03ae34652cd932ab4c91c71c511793df75c",
    "vendor": "Linux",
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    "ai_score": 0
}