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Vulnerability · Published Jul 19, 2026 · Assigned by Linux

CVE-2026-64065netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 94.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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 30%. while true; do sudo ./check generic/013 done [ 9849.452376] page: refcount:3 mapcount:0 mapping:00000000e58ff252 index:0x10781 pfn:0x1c322 [ 9849.452412] memcg:ffff8881a1915800 [ 9849.452417] aops:ceph_aops ino:1000058db9e dentry name(?):"f9XXXXXX" [ 9849.452432] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) [ 9849.452441] raw: 0017ffffc0000000 0000000000000000 dead000000000122 ffff88816110d248 [ 9849.452445] raw: 0000000000010781 0000000000000000 00000003ffffffff ffff8881a1915800 [ 9849.452447] page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio)) [ 9849.452474] ------------[ cut here ]------------ [ 9849.452476] kernel BUG at mm/filemap.c:1504! [ 9849.478635] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI [ 9849.481772] CPU: 2 UID: 0 PID: 84223 Comm: fsstress Not tainted 7.0.0-rc1+ #18 PREEMPT(full) [ 9849.482881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/1 0/2025 [ 9849.484539] RIP: 0010:folio_unlock+0x85/0xa0 [ 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 cc 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 [ 9849.493818] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246 [ 9849.495740] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000 [ 9849.498678] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 9849.500559] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000 [ 9849.501097] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000 [ 9849.502108] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000 [ 9849.502516] FS: 00007e36cbe94740(0000) GS:ffff88824a899000(0000) knlGS:0000000000000000 [ 9849.502996] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9849.503810] CR2: 000000c0002b0000 CR3: 000000011bbf6004 CR4: 0000000000772ef0 [ 9849.504459] PKRU: 55555554 [ 9849.504626] Call Trace: [ 9849.505242] <TASK> [ 9849.505379] netfs_write_begin+0x7c8/0x10a0 [ 9849.505877] ? __kasan_check_read+0x11/0x20 [ 9849.506384] ? __pfx_netfs_write_begin+0x10/0x10 [ 9849.507178] ceph_write_begin+0x8c/0x1c0 [ 9849.507934] generic_perform_write+0x391/0x8f0 [ 9849.508503] ? __pfx_generic_perform_write+0x10/0x10 [ 9849.509062] ? file_update_time_flags+0x19a/0x4b0 [ 9849.509581] ? ceph_get_caps+0x63/0xf0 [ 9849.510259] ? ceph_get_caps+0x63/0xf0 [ 9849.510530] ceph_write_iter+0xe79/0x1ae0 [ 9849.511282] ? __pfx_ceph_write_iter+0x10/0x10 [ 9849.511839] ? lock_acquire+0x1ad/0x310 [ 9849.512334] ? ksys_write+0xf9/0x230 [ 9849.512582] ? lock_is_held_type+0xaa/0x140 [ 9849.513128] vfs_write+0x512/0x1110 [ 9849.513634] ? __fget_files+0x33/0x350 [ 9849.513893] ? __pfx_vfs_write+0x10/0x10 [ 9849.514143] ? mutex_lock_nested+0x1b/0x30 [ 9849.514394] ksys_write+0xf9/0x230 [ 9849.514621] ? __pfx_ksys_write+0x10/0x10 [ 9849.514887] ? do_syscall_64+0x25e/0x1520 [ 9849.515122] ? __kasan_check_read+0x11/0x20 [ 9849.515366] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.515655] __x64_sys_write+0x72/0xd0 [ 9849.515885] ? trace_hardirqs_on+0x24/0x1c0 [ 9849.516130] x64_sys_call+0x22f/0x2390 [ 9849.516341] do_syscall_64+0x12b/0x1520 [ 9849.516545] ? do_syscall_64+0x27c/0x1520 [ 9849.516783] ? do_syscall_64+0x27c/0x1520 [ 9849.517003] ? lock_release+0x318/0x480 [ 9849.517220] ? __x64_sys_io_getevents+0x143/0x2d0 [ 9849.517479] ? percpu_ref_put_many.constprop.0+0x8f/0x210 [ 9849.517779] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 9849.518073] ? do_syscall_64+0x25e/0x1520 [ 9849.518291] ? __kasan_check_read+0x11/0x20 [ 9849.518519] ? trace_hardirqs_on_prepare+0x178/0x1c0 [ 9849.518799] ? do_syscall_64+0x27c/0x1520 [ 9 ---truncated---

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.94-1DEBIAN-CVE-2026-64065
Debian:14linux7.0.12-1DEBIAN-CVE-2026-64065
Ubuntu:26.04:LTSlinux7.0.0-28.28UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-aws7.0.0-1009.9UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-gcp7.0.0-1008.8UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-gke7.0.0-1003.4UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-28.28~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-ibm7.0.0-1010.10UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1016.16UBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1016.16~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2016.16UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1009.9UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-oracle7.0.0-1008.8UBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-raspi7.0.0-1015.15UBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-realtime7.0.0-28.28.1UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64065
Ubuntu:26.04:LTSlinux-riscv7.0.0-28.28.1UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-64065
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-28.28.1~24.04.3UBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-64065
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-64065

Affected products (as reported)

VendorProductVersions
Linux Linux ee4cdf7ba857a894ad1650d6ab77669cbbfa329e – before 51ffb788f074c0a61953086f49008028c1e7b645ee4cdf7ba857a894ad1650d6ab77669cbbfa329e – before b63971238beb79cf701dac33c6cefc56c07c89faee4cdf7ba857a894ad1650d6ab77669cbbfa329e – before 5ad05b6f5df296ef046589f222bb2587495b991eee4cdf7ba857a894ad1650d6ab77669cbbfa329e – before dc7832d05deb4d632e8035e3299e31a3528fa0d0
Linux Linux 6.12

References