{"id":"CVE-2026-64065","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-64065","generatedAt":"2026-10-28T04:11:52.776Z","title":"In the Linux kernel, the following vulnerability has been resolved: netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call The multiple runs of generic/013 test-case is capable to reproduce a kernel BUG at mm/filemap.c:1504 with probability of…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call\n\nThe multiple runs of generic/013 test-case is capable\nto reproduce a kernel BUG at mm/filemap.c:1504 with\nprobability of 30%.\n\nwhile true; do\n  sudo ./check generic/013\ndone\n\n[ 9849.452376] page: refcount:3 mapcount:0 mapping:00000000e58ff252 index:0x10781 pfn:0x1c322\n[ 9849.452412] memcg:ffff8881a1915800\n[ 9849.452417] aops:ceph_aops ino:1000058db9e dentry name(?):\"f9XXXXXX\"\n[ 9849.452432] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)\n[ 9849.452441] raw: 0017ffffc0000000 0000000000000000 dead000000000122 ffff88816110d248\n[ 9849.452445] raw: 0000000000010781 0000000000000000 00000003ffffffff ffff8881a1915800\n[ 9849.452447] page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))\n[ 9849.452474] ------------[ cut here ]------------\n[ 9849.452476] kernel BUG at mm/filemap.c:1504!\n[ 9849.478635] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n[ 9849.481772] CPU: 2 UID: 0 PID: 84223 Comm: fsstress Not tainted 7.0.0-rc1+ #18 PREEMPT(full)\n[ 9849.482881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/1\n0/2025\n[ 9849.484539] RIP: 0010:folio_unlock+0x85/0xa0\n[ 9849.485076] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc\ncc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84\n[ 9849.493818] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246\n[ 9849.495740] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000\n[ 9849.498678] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n[ 9849.500559] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000\n[ 9849.501097] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000\n[ 9849.502108] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000\n[ 9849.502516] FS:  00007e36cbe94740(0000) GS:ffff88824a899000(0000) knlGS:0000000000000000\n[ 9849.502996] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 9849.503810] CR2: 000000c0002b0000 CR3: 000000011bbf6004 CR4: 0000000000772ef0\n[ 9849.504459] PKRU: 55555554\n[ 9849.504626] Call Trace:\n[ 9849.505242]  <TASK>\n[ 9849.505379]  netfs_write_begin+0x7c8/0x10a0\n[ 9849.505877]  ? __kasan_check_read+0x11/0x20\n[ 9849.506384]  ? __pfx_netfs_write_begin+0x10/0x10\n[ 9849.507178]  ceph_write_begin+0x8c/0x1c0\n[ 9849.507934]  generic_perform_write+0x391/0x8f0\n[ 9849.508503]  ? __pfx_generic_perform_write+0x10/0x10\n[ 9849.509062]  ? file_update_time_flags+0x19a/0x4b0\n[ 9849.509581]  ? ceph_get_caps+0x63/0xf0\n[ 9849.510259]  ? ceph_get_caps+0x63/0xf0\n[ 9849.510530]  ceph_write_iter+0xe79/0x1ae0\n[ 9849.511282]  ? __pfx_ceph_write_iter+0x10/0x10\n[ 9849.511839]  ? lock_acquire+0x1ad/0x310\n[ 9849.512334]  ? ksys_write+0xf9/0x230\n[ 9849.512582]  ? lock_is_held_type+0xaa/0x140\n[ 9849.513128]  vfs_write+0x512/0x1110\n[ 9849.513634]  ? __fget_files+0x33/0x350\n[ 9849.513893]  ? __pfx_vfs_write+0x10/0x10\n[ 9849.514143]  ? mutex_lock_nested+0x1b/0x30\n[ 9849.514394]  ksys_write+0xf9/0x230\n[ 9849.514621]  ? __pfx_ksys_write+0x10/0x10\n[ 9849.514887]  ? do_syscall_64+0x25e/0x1520\n[ 9849.515122]  ? __kasan_check_read+0x11/0x20\n[ 9849.515366]  ? trace_hardirqs_on_prepare+0x178/0x1c0\n[ 9849.515655]  __x64_sys_write+0x72/0xd0\n[ 9849.515885]  ? trace_hardirqs_on+0x24/0x1c0\n[ 9849.516130]  x64_sys_call+0x22f/0x2390\n[ 9849.516341]  do_syscall_64+0x12b/0x1520\n[ 9849.516545]  ? do_syscall_64+0x27c/0x1520\n[ 9849.516783]  ? do_syscall_64+0x27c/0x1520\n[ 9849.517003]  ? lock_release+0x318/0x480\n[ 9849.517220]  ? __x64_sys_io_getevents+0x143/0x2d0\n[ 9849.517479]  ? percpu_ref_put_many.constprop.0+0x8f/0x210\n[ 9849.517779]  ? entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[ 9849.518073]  ? do_syscall_64+0x25e/0x1520\n[ 9849.518291]  ? __kasan_check_read+0x11/0x20\n[ 9849.518519]  ? trace_hardirqs_on_prepare+0x178/0x1c0\n[ 9849.518799]  ? do_syscall_64+0x27c/0x1520\n[ 9\n---truncated---","published":"2026-07-19T16:17:47.000Z","lastModified":"2026-09-03T15:35:54.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00162,"percentile":0.0531,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.16%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/51ffb788f074c0a61953086f49008028c1e7b645","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5ad05b6f5df296ef046589f222bb2587495b991e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b63971238beb79cf701dac33c6cefc56c07c89fa","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dc7832d05deb4d632e8035e3299e31a3528fa0d0","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64065","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}