dbcve.org
Linux KernelOperating system · Linux

CVE-2026-43491

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-19
Fix available
A fix is available. Upgrade to 6.6.140 / 6.12.86 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: net: qrtr: ns: Limit the maximum server registration per node Current code does no bound checking on the number of servers added per node. A malicious client can flood NEW_SERVER messages and exhaust memory. Fix this issue by limiting the maximum number of server registrations to 256 per node. If the NEW_SERVER message is received for an old port, then don't restrict it as it will get replaced. While at it, also rate limit the error messages in the failure path of qrtr_ns_worker(). Note that the limit of 256 is chosen based on the current platform requirements. If requirement changes in the future, this limit can be increased.

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, < 6.6.140>= 6.7, < 6.12.86>= 6.13, < 6.18.27>= 6.19, < 7.0.4

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 6.6.140 / 6.12.86 / 6.18.27 or later
Fixed in 6.6.1406.12.866.18.27
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel >= 6.6.140 (for 6.6.y branch), >= 6.12.86 (for 6.12.y branch), >= 6.18.27 (for 6.18.y branch), or >= 7.0.4 (for 7.0.y branch)

  1. Identify the currently running Linux kernel version using 'uname -r' or 'hostnamectl'
  2. Determine which stable branch your current kernel version belongs to based on the affected version ranges (6.6.y, 6.12.y, 6.18.y, or 7.0.y)
  3. Upgrade the Linux kernel to a patched version: for 6.6.y series upgrade to >= 6.6.140, for 6.7-6.11 upgrade to >= 6.12.86, for 6.13-6.17 upgrade to >= 6.18.27, or for 6.19+ upgrade to >= 7.0.4
  4. On Debian/Ubuntu: 'sudo apt-get update && sudo apt-get dist-upgrade' or manually install the kernel package
  5. On RHEL/CentOS: 'sudo yum update kernel' or 'sudo dnf update kernel'
  6. On Fedora: 'sudo dnf update kernel'
  7. Reboot the system to load the new kernel: 'sudo reboot'
  8. Verify the new kernel version is running: 'uname -r'
Caveat Kernel upgrades may require rebuilding third-party kernel modules and could introduce slight API changes; ensure backup of critical data and test in staging if possible

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

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-43491 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-43491 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data