GHSA-XX5J-8788-QWJ6
Vulnerability from github – Published: 2025-08-22 18:31 – Updated: 2026-01-07 18:30In the Linux kernel, the following vulnerability has been resolved:
net: appletalk: Fix use-after-free in AARP proxy probe
The AARP proxy‐probe routine (aarp_proxy_probe_network) sends a probe, releases the aarp_lock, sleeps, then re-acquires the lock. During that window an expire timer thread (__aarp_expire_timer) can remove and kfree() the same entry, leading to a use-after-free.
race condition:
cpu 0 | cpu 1
atalk_sendmsg() | atif_proxy_probe_device()
aarp_send_ddp() | aarp_proxy_probe_network()
mod_timer() | lock(aarp_lock) // LOCK!!
timeout around 200ms | alloc(aarp_entry)
and then call | proxies[hash] = aarp_entry
aarp_expire_timeout() | aarp_send_probe()
| unlock(aarp_lock) // UNLOCK!!
lock(aarp_lock) // LOCK!! | msleep(100);
__aarp_expire_timer(&proxies[ct]) |
free(aarp_entry) |
unlock(aarp_lock) // UNLOCK!! |
| lock(aarp_lock) // LOCK!!
| UAF aarp_entry !!
================================================================== BUG: KASAN: slab-use-after-free in aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 Read of size 4 at addr ffff8880123aa360 by task repro/13278
CPU: 3 UID: 0 PID: 13278 Comm: repro Not tainted 6.15.2 #3 PREEMPT(full) Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc1/0x630 mm/kasan/report.c:521 kasan_report+0xca/0x100 mm/kasan/report.c:634 aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818 sock_do_ioctl+0xdc/0x260 net/socket.c:1190 sock_ioctl+0x239/0x6a0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x194/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Allocated: aarp_alloc net/appletalk/aarp.c:382 [inline] aarp_proxy_probe_network+0xd8/0x630 net/appletalk/aarp.c:468 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818
Freed: kfree+0x148/0x4d0 mm/slub.c:4841 __aarp_expire net/appletalk/aarp.c:90 [inline] __aarp_expire_timer net/appletalk/aarp.c:261 [inline] aarp_expire_timeout+0x480/0x6e0 net/appletalk/aarp.c:317
The buggy address belongs to the object at ffff8880123aa300 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 96 bytes inside of freed 192-byte region [ffff8880123aa300, ffff8880123aa3c0)
Memory state around the buggy address: ffff8880123aa200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880123aa280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880123aa300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880123aa380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880123aa400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================
{
"affected": [],
"aliases": [
"CVE-2025-38666"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-22T16:15:42Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: appletalk: Fix use-after-free in AARP proxy probe\n\nThe AARP proxy\u2010probe routine (aarp_proxy_probe_network) sends a probe,\nreleases the aarp_lock, sleeps, then re-acquires the lock. During that\nwindow an expire timer thread (__aarp_expire_timer) can remove and\nkfree() the same entry, leading to a use-after-free.\n\nrace condition:\n\n cpu 0 | cpu 1\n atalk_sendmsg() | atif_proxy_probe_device()\n aarp_send_ddp() | aarp_proxy_probe_network()\n mod_timer() | lock(aarp_lock) // LOCK!!\n timeout around 200ms | alloc(aarp_entry)\n and then call | proxies[hash] = aarp_entry\n aarp_expire_timeout() | aarp_send_probe()\n | unlock(aarp_lock) // UNLOCK!!\n lock(aarp_lock) // LOCK!! | msleep(100);\n __aarp_expire_timer(\u0026proxies[ct]) |\n free(aarp_entry) |\n unlock(aarp_lock) // UNLOCK!! |\n | lock(aarp_lock) // LOCK!!\n | UAF aarp_entry !!\n\n==================================================================\nBUG: KASAN: slab-use-after-free in aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493\nRead of size 4 at addr ffff8880123aa360 by task repro/13278\n\nCPU: 3 UID: 0 PID: 13278 Comm: repro Not tainted 6.15.2 #3 PREEMPT(full)\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:408 [inline]\n print_report+0xc1/0x630 mm/kasan/report.c:521\n kasan_report+0xca/0x100 mm/kasan/report.c:634\n aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493\n atif_proxy_probe_device net/appletalk/ddp.c:332 [inline]\n atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857\n atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818\n sock_do_ioctl+0xdc/0x260 net/socket.c:1190\n sock_ioctl+0x239/0x6a0 net/socket.c:1311\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:906 [inline]\n __se_sys_ioctl fs/ioctl.c:892 [inline]\n __x64_sys_ioctl+0x194/0x200 fs/ioctl.c:892\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xcb/0x250 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\nAllocated:\n aarp_alloc net/appletalk/aarp.c:382 [inline]\n aarp_proxy_probe_network+0xd8/0x630 net/appletalk/aarp.c:468\n atif_proxy_probe_device net/appletalk/ddp.c:332 [inline]\n atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857\n atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818\n\nFreed:\n kfree+0x148/0x4d0 mm/slub.c:4841\n __aarp_expire net/appletalk/aarp.c:90 [inline]\n __aarp_expire_timer net/appletalk/aarp.c:261 [inline]\n aarp_expire_timeout+0x480/0x6e0 net/appletalk/aarp.c:317\n\nThe buggy address belongs to the object at ffff8880123aa300\n which belongs to the cache kmalloc-192 of size 192\nThe buggy address is located 96 bytes inside of\n freed 192-byte region [ffff8880123aa300, ffff8880123aa3c0)\n\nMemory state around the buggy address:\n ffff8880123aa200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n ffff8880123aa280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc\n\u003effff8880123aa300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ^\n ffff8880123aa380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n ffff8880123aa400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n==================================================================",
"id": "GHSA-xx5j-8788-qwj6",
"modified": "2026-01-07T18:30:22Z",
"published": "2025-08-22T18:31:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38666"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/186942d19c0222617ef61f50e1dba91e269a5963"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2a6209e4649d45fd85d4193abc481911858ffc6f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5f02ea0f63dd38c41539ea290fcc1693c73aa8e5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6c4a92d07b0850342d3becf2e608f805e972467c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/82d19a70ced28b17a38ebf1b6978c6c7db894979"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b35694ffabb2af308a1f725d70f60fd8a47d1f3e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e4f1564c5b699eb89b3040688fd6b4e57922f1f6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f90b6bb203f3f38bf2b3d976113d51571df9a482"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
}
],
"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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