Answer in brief
CVE-2025-39866 records a High severity (CVSS 7.8) vulnerability in fs: writeback: fix use-after-free in __mark_inode_dirty(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=0747259d13febfcc838980a63c414c9b920cea6f <e2a14bbae5d8bacaa301362744a110e2be40a3a3 || >=0747259d13febfcc838980a63c414c9b920cea6f <b187c976111960e6e54a6b1fff724f6e3d39406c || >=0747259d13febfcc838980a63c414c9b920cea6f <1edc2feb9c759a9883dfe81cb5ed231412d8b2e4 || >=0747259d13febfcc838980a63c414c9b920cea6f <bf89b1f87c72df79cf76203f71fbf8349cd5c9de || >=0747259d13febfcc838980a63c414c9b920cea6f <e63052921f1b25a836feb1500b841bff7a4a0456 || >=0747259d13febfcc838980a63c414c9b920cea6f <c8c14adf80bd1a6e4a1d7ee9c2a816881c26d17a || >=0747259d13febfcc838980a63c414c9b920cea6f <d02d2c98d25793902f65803ab853b592c7a96b29 | e2a14bbae5d8bacaa301362744a110e2be40a3a3, b187c976111960e6e54a6b1fff724f6e3d39406c, 1edc2feb9c759a9883dfe81cb5ed231412d8b2e4, bf89b1f87c72df79cf76203f71fbf8349cd5c9de, e63052921f1b25a836feb1500b841bff7a4a0456, c8c14adf80bd1a6e4a1d7ee9c2a816881c26d17a, d02d2c98d25793902f65803ab853b592c7a96b29 |
| Linux/Linuxgeneric | 4.2 | Not reported |
| Siemens/SIMATIC CN 4100generic | >=0 <V5.0 | V5.0 |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
Published upstream
Sep 19, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: fs: writeback: fix use-after-free in __mark_inode_dirty() An use-after-free issue occurred when __mark_inode_dirty() get the bdi_writeback that was in the progress of switching. CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1 ...... pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __mark_inode_dirty+0x124/0x418 lr : __mark_inode_dirty+0x118/0x418 sp : ffffffc08c9dbbc0 ........ Call trace: __mark_inode_dirty+0x124/0x418 generic_update_time+0x4c/0x60 file_modified+0xcc/0xd0 ext4_buffered_write_iter+0x58/0x124 ext4_file_write_iter+0x54/0x704 vfs_write+0x1c0/0x308 ksys_write+0x74/0x10c __arm64_sys_write+0x1c/0x28 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xc0/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x40/0xe4 el0t_64_sync_handler+0x120/0x12c el0t_64_sync+0x194/0x198 Root cause is: systemd-random-seed kworker ---------------------------------------------------------------------- ___mark_inode_dirty inode_switch_wbs_work_fn spin_lock(&inode->i_lock); inode_attach_wb locked_inode_to_wb_and_lock_list get inode->i_wb spin_unlock(&inode->i_lock); spin_lock(&wb->list_lock) spin_lock(&inode->i_lock) inode_io_list_move_locked spin_unlock(&wb->list_lock) spin_unlock(&inode->i_lock) spin_lock(&old_wb->list_lock) inode_do_switch_wbs spin_lock(&inode->i_lock) inode->i_wb = new_wb spin_unlock(&inode->i_lock) spin_unlock(&old_wb->list_lock) wb_put_many(old_wb, nr_switched) cgwb_release old wb released wb_wakeup_delayed() accesses wb, then trigger the use-after-free issue Fix this race condition by holding inode spinlock until wb_wakeup_delayed() finished.
Quoted source text, attributed separately from HOL analysis.