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Linux KernelOperating system · Linux

CVE-2026-43107

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-06
Fix available
A fix is available. Upgrade to 6.12.83 / 6.18.24 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: xfrm: account XFRMA_IF_ID in aevent size calculation xfrm_get_ae() allocates the reply skb with xfrm_aevent_msgsize(), then build_aevent() appends attributes including XFRMA_IF_ID when x->if_id is set. xfrm_aevent_msgsize() does not include space for XFRMA_IF_ID. For states with if_id, build_aevent() can fail with -EMSGSIZE and hit BUG_ON(err < 0) in xfrm_get_ae(), turning a malformed netlink interaction into a kernel panic. Account XFRMA_IF_ID in the size calculation unconditionally and replace the BUG_ON with normal error unwinding.

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:>= 4.19, < 6.12.83>= 6.13, < 6.18.24>= 6.19, < 6.19.14= 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
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 6.12.83 / 6.18.24 / 6.19.14 or later
Fixed in 6.12.836.18.246.19.14
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 6.12.83, 6.18.24, or 6.19.14 (depending on your branch)

  1. Check current kernel version with: uname -r
  2. Identify the appropriate upgrade path based on your current kernel branch (6.12.x, 6.13.x-6.17.x, 6.18.x, or 6.19.x)
  3. For RHEL/CentOS/Fedora: run 'sudo dnf update' or 'sudo yum update' to receive kernel packages
  4. For Debian/Ubuntu: run 'sudo apt update && sudo apt upgrade' to get the new kernel
  5. Reboot the system to load the patched kernel: sudo systemctl reboot
  6. Verify the new kernel is running with: uname -r
  7. Confirm the fix is applied by checking that xfrm_aevent_msgsize() now includes XFRMA_IF_ID in its calculation
Caveat Kernel upgrades may require system downtime for reboot; ensure compatibility of custom kernel modules with the new version before production deployment

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-2026-43107 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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