{"cve":"CVE-2025-38666","nvd":{"published":"2025-08-22T16:15:42.000","modified":"2026-06-17T09:17:36.923","status":"Analyzed","description":"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‐probe 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(&proxies[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 <TASK>\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 </TASK>\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>ffff8880123aa300: 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==================================================================","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/186942d19c0222617ef61f50e1dba91e269a5963","https://git.kernel.org/stable/c/2a6209e4649d45fd85d4193abc481911858ffc6f","https://git.kernel.org/stable/c/5f02ea0f63dd38c41539ea290fcc1693c73aa8e5","https://git.kernel.org/stable/c/6c4a92d07b0850342d3becf2e608f805e972467c","https://git.kernel.org/stable/c/82d19a70ced28b17a38ebf1b6978c6c7db894979"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:07:46.309729541+00:00"},"epss":{"cve":"CVE-2025-38666","score":0.00174,"percentile":0.06836,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}