{"id":"CVE-2025-39866","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: writeback: fix use-after-free in __mark_inode_dirty()\n\nAn use-after-free issue occurred when __mark_inode_dirty() get the\nbdi_writeback that was in the progress of …","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: writeback: fix use-after-free in __mark_inode_dirty()\n\nAn use-after-free issue occurred when __mark_inode_dirty() get the\nbdi_writeback that was in the progress of …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.2, < 5.10.247","linux_kernel >= 5.11, < 5.15.192","linux_kernel >= 5.16, < 6.1.151","linux_kernel >= 6.2, < 6.6.105","linux_kernel >= 6.7, < 6.12.46","linux_kernel >= 6.13, < 6.16.6","linux_kernel = 6.17","debian_linux = 11.0"],"patched":["linux_kernel 6.16.6"],"published":"2025-09-19","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:02.370","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-39866","references":[{"url":"https://git.kernel.org/stable/c/1edc2feb9c759a9883dfe81cb5ed231412d8b2e4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b187c976111960e6e54a6b1fff724f6e3d39406c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bf89b1f87c72df79cf76203f71fbf8349cd5c9de","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c8c14adf80bd1a6e4a1d7ee9c2a816881c26d17a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d02d2c98d25793902f65803ab853b592c7a96b29","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e2a14bbae5d8bacaa301362744a110e2be40a3a3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e63052921f1b25a836feb1500b841bff7a4a0456","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-032379.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","exploit-available","cve.org"],"epss":0.00314,"epssPercentile":0.2417,"exploits":{"github":1,"githubRepos":["https://github.com/byteReaper77/CVE-2025-39866"],"checkedAt":"2026-10-27T16:46:32.507Z"},"exploitAvailable":true,"ingestedAt":"2026-09-08T15:33:26.997Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:54:28.454479Z"},"slug":"CVE-2025-39866","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfs: writeback: fix use-after-free in __mark_inode_dirty()\n\nAn use-after-free issue occurred when __mark_inode_dirty() get the\nbdi_writeback that was in the progress of switching.\n\nCPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1\n......\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : __mark_inode_dirty+0x124/0x418\nlr : __mark_inode_dirty+0x118/0x418\nsp : ffffffc08c9dbbc0\n........\nCall trace:\n __mark_inode_dirty+0x124/0x418\n generic_update_time+0x4c/0x60\n file_modified+0xcc/0xd0\n ext4_buffered_write_iter+0x58/0x124\n ext4_file_write_iter+0x54/0x704\n vfs_write+0x1c0/0x308\n ksys_write+0x74/0x10c\n __arm64_sys_write+0x1c/0x28\n invoke_syscall+0x48/0x114\n el0_svc_common.constprop.0+0xc0/0xe0\n do_el0_svc+0x1c/0x28\n el0_svc+0x40/0xe4\n el0t_64_sync_handler+0x120/0x12c\n el0t_64_sync+0x194/0x198\n\nRoot cause is:\n\nsystemd-random-seed                         kworker\n----------------------------------------------------------------------\n___mark_inode_dirty                     inode_switch_wbs_work_fn\n\n  spin_lock(&inode->i_lock);\n  inode_attach_wb\n  locked_inode_to_wb_and_lock_list\n     get inode->i_wb\n     spin_unlock(&inode->i_lock);\n     spin_lock(&wb->list_lock)\n  spin_lock(&inode->i_lock)\n  inode_io_list_move_locked\n  spin_unlock(&wb->list_lock)\n  spin_unlock(&inode->i_lock)\n                                    spin_lock(&old_wb->list_lock)\n                                      inode_do_switch_wbs\n                                        spin_lock(&inode->i_lock)\n                                        inode->i_wb = new_wb\n                                        spin_unlock(&inode->i_lock)\n                                    spin_unlock(&old_wb->list_lock)\n                                    wb_put_many(old_wb, nr_switched)\n                                      cgwb_release\n                                      old wb released\n  wb_wakeup_delayed() accesses wb,\n  then trigger the use-after-free\n  issue\n\nFix this race condition by holding inode spinlock until\nwb_wakeup_delayed() finished.\n\n## Affected\n\n- `linux_kernel >= 4.2, < 5.10.247`\n- `linux_kernel >= 5.11, < 5.15.192`\n- `linux_kernel >= 5.16, < 6.1.151`\n- `linux_kernel >= 6.2, < 6.6.105`\n- `linux_kernel >= 6.7, < 6.12.46`\n- `linux_kernel >= 6.13, < 6.16.6`\n- `linux_kernel = 6.17`\n- `debian_linux = 11.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.16.6`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}