Linux KernelOperating system · Linux
CVE-2025-39731
A fix is available.
Upgrade to 6.1.148 / 6.6.102 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click
Patch available
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: f2fs: vm_unmap_ram() may be called from an invalid context When testing F2FS with xfstests using UFS backed virtual disks the kernel complains sometimes that f2fs_release_decomp_mem() calls vm_unmap_ram() from an invalid context. Example trace from f2fs/007 test: f2fs/007 5s ... [12:59:38][ 8.902525] run fstests f2fs/007 [ 11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978 [ 11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd [ 11.475357] preempt_count: 1, expected: 0 [ 11.476970] RCU nest depth: 0, expected: 0 [ 11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G W 6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none) [ 11.478535] Tainted: [W]=WARN [ 11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 11.478537] Call Trace: [ 11.478543] <TASK> [ 11.478545] dump_stack_lvl+0x4e/0x70 [ 11.478554] __might_resched.cold+0xaf/0xbe [ 11.478557] vm_unmap_ram+0x21/0xb0 [ 11.478560] f2fs_release_decomp_mem+0x59/0x80 [ 11.478563] f2fs_free_dic+0x18/0x1a0 [ 11.478565] f2fs_finish_read_bio+0xd7/0x290 [ 11.478570] blk_update_request+0xec/0x3b0 [ 11.478574] ? sbitmap_queue_clear+0x3b/0x60 [ 11.478576] scsi_end_request+0x27/0x1a0 [ 11.478582] scsi_io_completion+0x40/0x300 [ 11.478583] ufshcd_mcq_poll_cqe_lock+0xa3/0xe0 [ 11.478588] ufshcd_sl_intr+0x194/0x1f0 [ 11.478592] ufshcd_threaded_intr+0x68/0xb0 [ 11.478594] ? __pfx_irq_thread_fn+0x10/0x10 [ 11.478599] irq_thread_fn+0x20/0x60 [ 11.478602] ? __pfx_irq_thread_fn+0x10/0x10 [ 11.478603] irq_thread+0xb9/0x180 [ 11.478605] ? __pfx_irq_thread_dtor+0x10/0x10 [ 11.478607] ? __pfx_irq_thread+0x10/0x10 [ 11.478609] kthread+0x10a/0x230 [ 11.478614] ? __pfx_kthread+0x10/0x10 [ 11.478615] ret_from_fork+0x7e/0xd0 [ 11.478619] ? __pfx_kthread+0x10/0x10 [ 11.478621] ret_from_fork_asm+0x1a/0x30 [ 11.478623] </TASK> This patch modifies in_task() check inside f2fs_read_end_io() to also check if interrupts are disabled. This ensures that pages are unmapped asynchronously in an interrupt handler.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA detailed technical summary for this CVE is being prepared.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
Affected:
>= 6.0, < 6.1.148>= 6.2, < 6.6.102>= 6.7, < 6.12.42>= 6.13, < 6.15.10>= 6.16, < 6.16.1
Debian LinuxOperating system
Affected:
= 11.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped
Upgrade available
Upgrade to 6.1.148 / 6.6.102 / 6.12.42 or later
Fixed in
6.1.1486.6.1026.12.42
Vendor patch
git.kernel.org →
Recommended fix
High confidence
6.15.10 (or minimum 6.1.148 for 6.1.x, 6.6.102 for 6.6.x, 6.12.42 for 6.12.x, depending on current branch)
- 1. Identify the currently running kernel version using 'uname -r'
- 2. Determine which kernel branch you are currently on (e.g., 6.1.x, 6.6.x, 6.7.x, or 6.13+)
- 3. Upgrade the Linux kernel to a version that includes the fix: for 6.1.x upgrade to 6.1.148+, for 6.2-6.6.x upgrade to 6.6.102+, for 6.7-6.12.x upgrade to 6.12.42+, for 6.13-6.15.x upgrade to 6.15.10+
- 4. On Debian 11 (Bullseye), apply the Debian kernel patch from https://security-tracker.debian.org/tracker/CVE-2025-39731 or upgrade to a newer Debian release with the fixed kernel
- 5. Reboot the system to load the fixed kernel
- 6. Verify the fix is applied by checking 'uname -r' shows the patched version and monitoring for the vm_unmap_ram() context error no longer appearing
Caveat Standard kernel upgrade risks apply - ensure compatibility with custom modules and hardware drivers before rebooting
Generated from the published advisory — verify against the referenced sources before acting.
We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600.
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-39731 in production — separate from our analysis above.
Know something about CVE-2025-39731?
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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