{"cve":"CVE-2025-68367","nvd":{"published":"2025-12-24T11:16:00.267","modified":"2026-10-13T11:10:00.203","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmacintosh/mac_hid: fix race condition in mac_hid_toggle_emumouse\n\nThe following warning appears when running syzkaller, and this issue also\nexists in the mainline code.\n\n ------------[ cut here ]------------\n list_add double add: new=ffffffffa57eee28, prev=ffffffffa57eee28, next=ffffffffa5e63100.\n WARNING: CPU: 0 PID: 1491 at lib/list_debug.c:35 __list_add_valid_or_report+0xf7/0x130\n Modules linked in:\n CPU: 0 PID: 1491 Comm: syz.1.28 Not tainted 6.6.0+ #3\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\n RIP: 0010:__list_add_valid_or_report+0xf7/0x130\n RSP: 0018:ff1100010dfb7b78 EFLAGS: 00010282\n RAX: 0000000000000000 RBX: ffffffffa57eee18 RCX: ffffffff97fc9817\n RDX: 0000000000040000 RSI: ffa0000002383000 RDI: 0000000000000001\n RBP: ffffffffa57eee28 R08: 0000000000000001 R09: ffe21c0021bf6f2c\n R10: 0000000000000001 R11: 6464615f7473696c R12: ffffffffa5e63100\n R13: ffffffffa57eee28 R14: ffffffffa57eee28 R15: ff1100010dfb7d48\n FS:  00007fb14398b640(0000) GS:ff11000119600000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 0000000000000000 CR3: 000000010d096005 CR4: 0000000000773ef0\n DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n PKRU: 80000000\n Call Trace:\n  <TASK>\n  input_register_handler+0xb3/0x210\n  mac_hid_start_emulation+0x1c5/0x290\n  mac_hid_toggle_emumouse+0x20a/0x240\n  proc_sys_call_handler+0x4c2/0x6e0\n  new_sync_write+0x1b1/0x2d0\n  vfs_write+0x709/0x950\n  ksys_write+0x12a/0x250\n  do_syscall_64+0x5a/0x110\n  entry_SYSCALL_64_after_hwframe+0x78/0xe2\n\nThe WARNING occurs when two processes concurrently write to the mac-hid\nemulation sysctl, causing a race condition in mac_hid_toggle_emumouse().\nBoth processes read old_val=0, then both try to register the input handler,\nleading to a double list_add of the same handler.\n\n  CPU0                             CPU1\n  -------------------------        -------------------------\n  vfs_write() //write 1            vfs_write()  //write 1\n    proc_sys_write()                 proc_sys_write()\n      mac_hid_toggle_emumouse()          mac_hid_toggle_emumouse()\n        old_val = *valp // old_val=0\n                                           old_val = *valp // old_val=0\n                                           mutex_lock_killable()\n                                           proc_dointvec() // *valp=1\n                                           mac_hid_start_emulation()\n                                             input_register_handler()\n                                           mutex_unlock()\n        mutex_lock_killable()\n        proc_dointvec()\n        mac_hid_start_emulation()\n          input_register_handler() //Trigger Warning\n        mutex_unlock()\n\nFix this by moving the old_val read inside the mutex lock region.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/14c209835e47a87e6da94bb9401e570dcc14f31f","https://git.kernel.org/stable/c/1e4b207ffe54cf33a4b7a2912c4110f89c73bf3f","https://git.kernel.org/stable/c/230621ffdb361d15cd3ef92d8b4fa8d314f4fad4","https://git.kernel.org/stable/c/388391dd1cc567fcf0b372b63d414c119d23e911","https://git.kernel.org/stable/c/48a7d427eb65922b3f17fbe00e2bbc7cb9eac381"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:17:07.138532058+00:00"},"epss":{"cve":"CVE-2025-68367","score":0.00198,"percentile":0.09462,"date":"2026-10-25"},"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."]}