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Linux KernelOperating system · Linux

CVE-2025-22126

HIGH · 7.8 CVSS v3.1 Published 2025-04-16
Fix available
A fix is available. Upgrade to 6.1.135 / 6.6.88 or later.
See remediation →
80/100
Remediation priority · High
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: md: fix mddev uaf while iterating all_mddevs list While iterating all_mddevs list from md_notify_reboot() and md_exit(), list_for_each_entry_safe is used, and this can race with deletint the next mddev, causing UAF: t1: spin_lock //list_for_each_entry_safe(mddev, n, ...) mddev_get(mddev1) // assume mddev2 is the next entry spin_unlock t2: //remove mddev2 ... mddev_free spin_lock list_del spin_unlock kfree(mddev2) mddev_put(mddev1) spin_lock //continue dereference mddev2->all_mddevs The old helper for_each_mddev() actually grab the reference of mddev2 while holding the lock, to prevent from being freed. This problem can be fixed the same way, however, the code will be complex. Hence switch to use list_for_each_entry, in this case mddev_put() can free the mddev1 and it's not safe as well. Refer to md_seq_show(), also factor out a helper mddev_put_locked() to fix this problem.

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
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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, < 6.1.135>= 6.2, < 6.6.88>= 6.7, < 6.12.25>= 6.13, < 6.14.2

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 6.1.135 / 6.6.88 / 6.12.25 or later
Fixed in 6.1.1356.6.886.12.25
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel 6.1.135+ (6.0-6.1 branch), 6.6.88+ (6.2-6.6 branch), 6.12.25+ (6.7-6.12 branch), or 6.14.2+ (6.13+ branch)

  1. Identify your current Linux kernel version using `uname -r`
  2. Determine which version branch you are on from the affected ranges (>= 6.0 < 6.1.135, >= 6.2 < 6.6.88, >= 6.7 < 6.12.25, or >= 6.13 < 6.14.2)
  3. Upgrade the Linux kernel to a fixed version: 6.1.135 or later if on 6.0-6.1 branch; 6.6.88 or later if on 6.2-6.6 branch; 6.12.25 or later if on 6.7-6.12 branch; or 6.14.2 or later if on 6.13 branch
  4. Update boot loader configuration if necessary to ensure the new kernel is selected on next reboot
  5. Reboot the system to load the patched kernel
  6. Verify the running kernel version with `uname -r` to confirm the fix is applied
Caveat Kernel upgrades may require matching system utilities and drivers; ensure compatibility with user-space tools and any proprietary kernel modules 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 $3,200. 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-2025-22126 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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