What is CVE-2026-43491?

CVE-2026-43491 is a unscored severity Linux kernel vulnerability, affecting Linux kernel versions from 5.7 onward and patched in 6.6.140, 6.12.86, 6.18.27 and others. CVE-2026-43491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43491?

CVE-2026-43491 has a CVSS score of pending NVD analysis out of 10, rated awaiting scoring severity.

Is there a patch available for CVE-2026-43491?

Yes, CVE-2026-43491 has been patched. Fixed versions include 6.6.140, 6.12.86, 6.18.27 and others. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43491 actively exploited?

CVE-2026-43491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43491

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.

Package Linux Kernel

Published 2026-05-19

Last modified 2026-05-22

Patch available

Yes

Affected versions

Linux kernel versions 5.7 and later are affected. Fixed in 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1-rc1 and their respective stable series.

Affected from

≥ 5.7

Fixed in

✓ 6.6.140 6.6.x ✓ 6.12.86 6.12.x ✓ 6.18.27 6.18.x ✓ 7.0.4 7.0.x ✓ 7.1-rc1

References

The following references provide additional information about CVE-2026-43491 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/35fb4a0c077c5d1049c2628b769e0a1b1e65df0d
Patch
Kernel patch commit
https://git.kernel.org/stable/c/3efaad55cad1ded429e3a873bfece389058a526b
Patch
Kernel patch commit
https://git.kernel.org/stable/c/868202aa2adae427060a42d5bd663b4d782ec02c
Patch

5 patch commits total View all on NVD

Frequently asked questions

What is CVE-2026-43491?

CVE-2026-43491 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.7 onward and has been patched in 6.6.140, 6.12.86, 6.18.27 and others. CVE-2026-43491 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
Is there a patch available for CVE-2026-43491?

Yes — CVE-2026-43491 has been patched. Fixed versions include 6.6.140, 6.12.86, 6.18.27 and others. If you are running Linux kernel 5.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43491 actively exploited?

No — CVE-2026-43491 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.