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Linux KernelOperating system · Linux

CVE-2026-23274

HIGH · 7.8 CVSS v3.1 Published 2026-03-20
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: netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels IDLETIMER revision 0 rules reuse existing timers by label and always call mod_timer() on timer->timer. If the label was created first by revision 1 with XT_IDLETIMER_ALARM, the object uses alarm timer semantics and timer->timer is never initialized. Reusing that object from revision 0 causes mod_timer() on an uninitialized timer_list, triggering debugobjects warnings and possible panic when panic_on_warn=1. Fix this by rejecting revision 0 rule insertion when an existing timer with the same label is of ALARM type.

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:>= 5.7, < 5.10.253>= 5.11, < 5.15.203>= 5.16, < 6.1.167>= 6.2, < 6.6.130>= 6.7, < 6.12.78>= 6.13, < 6.18.19>= 6.19, < 6.19.9= 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 / 6.1.167 or later
Fixed in 5.10.2535.15.2036.1.167
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel 5.10.253, 5.15.203, 6.1.167, or 6.6.130 (or any later stable release)

  1. Identify the currently running kernel version using 'uname -r'
  2. Determine which version branch your kernel comes from (e.g., 5.15.x, 6.1.x, 6.6.x)
  3. Schedule a maintenance window for the kernel upgrade (requires system reboot)
  4. Upgrade the Linux kernel package to one of the fixed versions: 5.10.253, 5.15.203, 6.1.167, or 6.6.130 (or any later stable version)
  5. Reboot the system to load the new kernel
  6. Verify the new kernel version is running with 'uname -r'
  7. Confirm the fix is present by checking that the xt_IDLETIMER revision 0 rules with alarm timer labels are now rejected
Caveat Kernel upgrade requires system reboot; ensure compatibility of other software with the new kernel version

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-2026-23274 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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