What is CVE-2026-43417?

CVE-2026-43417 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-2026-43417 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43417?

CVE-2026-43417 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-2026-43417?

Yes, CVE-2026-43417 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-2026-43417 actively exploited?

CVE-2026-43417 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43417

Medium

In the Linux kernel, the following vulnerability has been resolved: sched/mmcid: Handle vfork()/CLONE_VM correctly Matthieu and Jiri reported stalls where a task endlessly loops in mm_get_cid() when scheduling in. It turned out that the logic which handles vfork()'ed tasks is broken. It is invoked when the number of tasks associated to a process is smaller than the number of MMCID users. It then walks the task list to find the vfork()'ed task, but accounts all the already processed tasks as well. If that double processing brings the number of to be handled tasks to 0, the walk stops and the vfork()'ed task's CID is not fixed up. As a consequence a subsequent schedule in fails to acquire a (transitional) CID and the machine stalls. Cure this by removing the accounting condition and make the fixup always walk the full task list if it could not find the exact number of users in the process' thread list.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-22

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-2026-43417 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/28b5a1395036d6c7a6c8034d85ad3d7d365f192c
Patch
Kernel patch commit
https://git.kernel.org/stable/c/e6761cdce78a8919a537989afb6aaf6881469f83
Patch

Details

CVE ID CVE-2026-43417

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-05-08

Modified 2026-05-22

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43417?

CVE-2026-43417 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-2026-43417 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43417?

CVE-2026-43417 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-2026-43417?

Yes — CVE-2026-43417 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-2026-43417 actively exploited?

No — CVE-2026-43417 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.