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Linux KernelOperating system · Linux

CVE-2026-23408

HIGH · 7.8 CVSS v3.1 Published 2026-04-01
Fix available
A fix is available. Upgrade to 5.10.253 / 5.15.203 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: apparmor: Fix double free of ns_name in aa_replace_profiles() if ns_name is NULL after 1071 error = aa_unpack(udata, &lh, &ns_name); and if ent->ns_name contains an ns_name in 1089 } else if (ent->ns_name) { then ns_name is assigned the ent->ns_name 1095 ns_name = ent->ns_name; however ent->ns_name is freed at 1262 aa_load_ent_free(ent); and then again when freeing ns_name at 1270 kfree(ns_name); Fix this by NULLing out ent->ns_name after it is transferred to ns_name ")

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-415

The same block of memory is freed twice, corrupting the allocator's bookkeeping in ways an attacker can shape toward code execution. It usually stems from tangled ownership of a pointer. The fix is clear, single ownership of each allocation and clearing pointers once they are freed.

General guidance for the double 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:>= 5.5.1, < 5.10.253>= 5.11, < 5.15.203>= 5.16, < 6.1.169>= 6.2, < 6.6.130>= 6.7, < 6.12.77>= 6.13, < 6.18.18>= 6.19, < 6.19.8= 5.5= 7.0

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 5.10.253 / 5.15.203 / 6.1.169 or later
Fixed in 5.10.2535.15.2036.1.169
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel 6.6.130 (or latest stable in your branch: 5.10.253+, 5.15.203+, 6.1.169+)

  1. 1. Identify the current running Linux kernel version using 'uname -r'
  2. 2. Check if the running version falls within any of the affected ranges: >= 5.5.1 and < 5.10.253, >= 5.11 and < 5.15.203, >= 5.16 and < 6.1.169, or >= 6.2 and < 6.6.130
  3. 3. If affected, schedule a maintenance window for kernel upgrade
  4. 4. Upgrade the Linux kernel to version 5.10.253 or later, 5.15.203 or later, 6.1.169 or later, or 6.6.130 or later depending on your branch
  5. 5. After reboot, verify the kernel version with 'uname -r' to confirm the fix is applied
  6. 6. Verify the AppArmor subsystem is functioning correctly post-upgrade
Caveat Kernel upgrades may require rebuilding third-party kernel modules and rebooting; ensure compatibility with userspace components and verify critical system services after upgrade

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 $1,950. 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-2026-23408 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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