What is CVE-2026-43390?

CVE-2026-43390 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.19 onward and patched in 6.19.9 and 7.0. CVE-2026-43390 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43390?

CVE-2026-43390 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-43390?

Yes, CVE-2026-43390 has been patched. Fixed versions include 6.19.9 and 7.0. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43390 actively exploited?

CVE-2026-43390 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43390

Medium

In the Linux kernel, the following vulnerability has been resolved: nstree: tighten permission checks for listing Even privileged services should not necessarily be able to see other privileged service's namespaces so they can't leak information to each other. Use may_see_all_namespaces() helper that centralizes this policy until the nstree adapts.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-26

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 6.19 and later are affected. Fixed in 6.19.9, 7.0 and their respective stable series.

Affected from

≥ 6.19

Fixed in

✓ 6.19.9 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43390 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/0abd81645fc95ec6a9d4e4813000f22c5efc0ff4
Patch
Kernel patch commit
https://git.kernel.org/stable/c/8d76afe84fa2babf604b3c173730d4d2b067e361
Patch

Details

CVE ID CVE-2026-43390

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-05-08

Modified 2026-05-26

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43390?

CVE-2026-43390 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.19 onward and has been patched in 6.19.9 and 7.0. CVE-2026-43390 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43390?

CVE-2026-43390 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-43390?

Yes — CVE-2026-43390 has been patched. Fixed versions include 6.19.9 and 7.0. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43390 actively exploited?

No — CVE-2026-43390 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.