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Linux KernelOperating system · Linux

CVE-2025-39829

MEDIUM · 5.5 CVSS v3.1 Published 2025-09-16
Fix available
A fix is available. Upgrade to 6.12.45 / 6.16.5 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 · unedited
In the Linux kernel, the following vulnerability has been resolved: trace/fgraph: Fix the warning caused by missing unregister notifier This warning was triggered during testing on v6.16: notifier callback ftrace_suspend_notifier_call already registered WARNING: CPU: 2 PID: 86 at kernel/notifier.c:23 notifier_chain_register+0x44/0xb0 ... Call Trace: <TASK> blocking_notifier_chain_register+0x34/0x60 register_ftrace_graph+0x330/0x410 ftrace_profile_write+0x1e9/0x340 vfs_write+0xf8/0x420 ? filp_flush+0x8a/0xa0 ? filp_close+0x1f/0x30 ? do_dup2+0xaf/0x160 ksys_write+0x65/0xe0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f When writing to the function_profile_enabled interface, the notifier was not unregistered after start_graph_tracing failed, causing a warning the next time function_profile_enabled was written. Fixed by adding unregister_pm_notifier in the exception path.

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 analysis

A 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:>= 2.6.30, < 6.12.45>= 6.13, < 6.16.5= 6.17

CVSS 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 6.12.45 / 6.16.5 or later
Fixed in 6.12.456.16.5
Vendor patch git.kernel.org →
Recommended fix High confidence

6.12.45+, 6.16.5+, or 6.18+ (depending on which branch you're on)

  1. Identify the currently running kernel version using 'uname -r'
  2. Determine which version range your current kernel falls into (>= 2.6.30, < 6.12.45; >= 6.13, < 6.16.5; or = 6.17)
  3. Upgrade the kernel to a fixed version: for 6.12.x series upgrade to >= 6.12.45, for 6.13.x-6.16.x series upgrade to >= 6.16.5, for 6.17.x upgrade to the next stable release (6.18 or later)
  4. Reboot the system to load the fixed kernel
  5. Verify the fix by checking that writing to /proc/sys/kernel/function_profile_enabled multiple times no longer triggers the 'notifier callback already registered' warning
Caveat Kernel upgrades may require system reboots and could introduce compatibility issues with custom modules or specific hardware drivers

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. Get the upgrade done

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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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-39829 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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