Cloudanix VulnDB

CVE-2025-38577

None

CVSS

—

EPSS

0.2%

Published

Aug 19, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in Linux file-system handling can make computers using certain storage formats crash when files are being saved or cleaned up.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Use After Free
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Use-after-free in f2fs inode eviction path allows access to freed inode structures during list_del operations in f2fs_inode_synced, f2fs_update_inode and related writeback/checkpoint code, resulting in kernel panic via KASAN-detected invalid memory read.

Why it matters to the business

Systems using f2fs may experience sudden kernel crashes during unmount, sync or metadata writeback operations, leading to downtime, potential filesystem corruption and service interruption; low immediate risk given absence from KEV and low EPSS, though similar kernel issues have been chained by threat actors for container privilege escalation.

How an attack unfolds

An attacker with local access crafts filesystem operations that trigger inode eviction and concurrent writeback; the freed inode is then dereferenced in list operations inside f2fs_write_checkpoint and kill_f2fs_super, causing panic. Related Linux kernel CVEs have been exploited by threat actors for container escape on Container-Optimized OS.

How to fix it

Upgrade affected Linux kernel to commit 15df59809c54fbd687cdf27efbd2103a937459be or later; for listed Chainguard packages apply version 0.53.0-r0. Reboot systems after update and verify f2fs is not mounted until patched.

How to confirm the fix worked

Confirm kernel git commit or package version matches the fixed release; inspect fs/f2fs/super.c and fs/f2fs/inode.c for the corrected f2fs_inode_synced and f2fs_evict_inode logic; run syzkaller-style tests targeting f2fs eviction under writeback to ensure absence of the use-after-free.

Typical attack path

  1. Obtain local unprivileged access
  2. Create or mount an f2fs filesystem
  3. Perform file operations that allocate and evict inodes while triggering metadata sync
  4. Force writeback_single_inode and f2fs_sync_inode_meta paths to dereference freed memory
  5. Trigger kernel panic or attempt to leverage resulting memory corruption

How to detect it

Search kernel logs and dmesg for KASAN use-after-free reports referencing __list_del_entry_valid, f2fs_inode_synced, f2fs_update_inode or f2fs_write_checkpoint; correlate with task_work_run and exit paths on systems running f2fs.

  • BUG: KASAN: use-after-free in __list_del_entry_valid
  • f2fs_inode_synced+0xf7/0x2e0
  • f2fs_update_inode+0x74/0x1c40
  • f2fs_write_checkpoint
  • kill_f2fs_super

What your security team should do

  • Prioritize kernel and package upgrades within standard maintenance windows given low EPSS and no KEV listing
  • Disable or avoid f2fs on unpatched systems handling untrusted workloads
  • Monitor kernel logs for KASAN reports involving f2fs list operations
  • Review container runtime configurations to limit f2fs exposure in multi-tenant environments

The record

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid panic in f2fs_evict_inode As syzbot [1] reported as below: R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe17473450 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 Read of size 8 at addr ffff88812d962278 by task syz-executor/564 CPU: 1 PID: 564 Comm: syz-executor Tainted: G W 6.1.129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x158 lib/dump_stack.c:106 print_address_description+0x71/0x210 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:427 kasan_report+0x122/0x150 mm/kasan/report.c:531 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351 __list_del_entry_valid+0xa6/0x130 lib/list_debug.c:62 __list_del_entry include/linux/list.h:134 [inline] list_del_init include/linux/list.h:206 [inline] f2fs_inode_synced+0xf7/0x2e0 fs/f2fs/super.c:1531 f2fs_update_inode+0x74/0x1c40 fs/f2fs/inode.c:585 f2fs_update_inode_page+0x137/0x170 fs/f2fs/inode.c:703 f2fs_write_inode+0x4ec/0x770 fs/f2fs/inode.c:731 write_inode fs/fs-writeback.c:1460 [inline] __writeback_single_inode+0x4a0/0xab0 fs/fs-writeback.c:1677 writeback_single_inode+0x221/0x8b0 fs/fs-writeback.c:1733 sync_inode_metadata+0xb6/0x110 fs/fs-writeback.c:2789 f2fs_sync_inode_meta+0x16d/0x2a0 fs/f2fs/checkpoint.c:1159 block_operations fs/f2fs/checkpoint.c:1269 [inline] f2fs_write_checkpoint+0xca3/0x2100 fs/f2fs/checkpoint.c:1658 kill_f2fs_super+0x231/0x390 fs/f2fs/super.c:4668 deactivate_locked_super+0x98/0x100 fs/super.c:332 deactivate_super+0xaf/0xe0 fs/super.c:363 cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1186 __cleanup_mnt+0x19/0x20 fs/namespace.c:1193 task_work_run+0x1c6/0x230 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9fb/0x2410 kernel/exit.c:871 do_group_exit+0x210/0x2d0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f28b1b8e169 Code: Unable to access opcode bytes at 0x7f28b1b8e13f. RSP: 002b:00007ffe174710a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f28b1c10879 RCX: 00007f28b1b8e169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000002 R08: 00007ffe1746ee47 R09: 00007ffe17472360 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffe17472360 R13: 00007f28b1c10854 R14: 000000000000dae5 R15: 00007ffe17474520 </TASK> Allocated by task 569: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4f/0x2c0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x104/0x220 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] f2fs_alloc_inode+0x2d/0x340 fs/f2fs/super.c:1419 alloc_inode fs/inode.c:261 [inline] iget_locked+0x186/0x880 fs/inode.c:1373 f2fs_iget+0x55/0x4c60 fs/f2fs/inode.c:483 f2fs_lookup+0x366/0xab0 fs/f2fs/namei.c:487 __lookup_slow+0x2a3/0x3d0 fs/namei.c:1690 lookup_slow+0x57/0x70 fs/namei.c:1707 walk_component+0x2e6/0x410 fs/namei ---truncated---

Affected packages

Ecosystem Package Introduced Fixed
Debian:11 linux 0 No fix
Debian:12 linux 0 No fix
Debian:13 linux 0 No fix
Debian:14 linux 0 No fix
Debian:14 linux 0 6.16.3-1
Linux Kernel 4.8.0 5.4.297
Mageia:9 kernel 0 6.6.105-1.mga9
Mageia:9 kernel-linus 0 6.6.105-1.mga9
Mageia:9 kmod-virtualbox 0 7.1.10-10.mga9
Mageia:9 kmod-xtables-addons 0 3.24-86.mga9
Mageia:9 mageia-repos 0 9-4.mga9
Mageia:9 meta-task 0 9-4.mga9

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