Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid accessing...
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid accessing uninitialized curseg
syzbot reports a f2fs bug as below:
F2FS-fs (loop3): Stopped filesystem due to reason: 7
kworker/u8:7: attempt to access beyond end of device
BUG: unable to handle page fault for address: ffffed1604ea3dfa
RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline]
RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline]
RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline]
RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline]
RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649
f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline]
f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791
write_inode fs/fs-writeback.c:1525 [inline]
__writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745
writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976
wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156
wb_do_writeback fs/fs-writeback.c:2303 [inline]
wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
worker_thread+0x870/0xd30 kernel/workqueue.c:3398
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger
no free segment fault in allocator, then it will update curseg->segno to
NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed
to check the flag, and access invalid curseg->segno directly in below call
path, then resulting in panic:
- f2fs_write_inode
- f2fs_is_checkpoint_ready
- has_enough_free_secs
- has_not_enough_free_secs
- __get_secs_required- has_curseg_enough_space
- get_ckpt_valid_blocks
: access invalid curseg->segno
To avoid this issue, let's:
- check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in
f2fs_write_inode(). - in has_curseg_enough_space(), save curseg->segno into a temp variable,
and verify its validation before use.
Impact
CVE-2025-22123 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-22123? CVE-2025-22123 is a medium-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-22123? CVE-2025-22123 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-22123? No fixed version is listed for CVE-2025-22123 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-22123 exploitable, and should I be worried? Whether CVE-2025-22123 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-22123 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.