What is CVE-2026-43379?

CVE-2026-43379 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, classified as a Use After Free flaw (CWE-416), affecting Linux kernel versions from 6.6.32 onward and patched in 6.6.130, 6.12.78, 6.18.19 and others. CVE-2026-43379 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43379?

CVE-2026-43379 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-43379?

Yes, CVE-2026-43379 has been patched. Fixed versions include 6.6.130, 6.12.78, 6.18.19 and others. If you are running Linux kernel 6.6.32 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-43379 actively exploited?

CVE-2026-43379 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Use After Free (CWE-416)?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/416.html

CVE-2026-43379

Critical

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close() opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is being accessed after rcu_read_unlock() has been called. This creates a race condition where the memory could be freed by a concurrent writer between the unlock and the subsequent pointer dereferences (opinfo->is_lease, etc.), leading to a use-after-free.

Package Linux Kernel

Published 2026-05-08

Last modified 2026-05-19

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-416

CVE-2026-43379 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.6.32, 6.9 and later are affected. Fixed in 6.6.130, 6.12.78, 6.18.19, 6.19.9, 7.0 and their respective stable series.

Affected from

≥ 6.6.32 ≥ 6.9

Fixed in

✓ 6.6.130 6.6.x ✓ 6.12.78 6.12.x ✓ 6.18.19 6.18.x ✓ 6.19.9 6.19.x ✓ 7.0

References

5 total

Kernel Git
https://git.kernel.org/stable/c/960699317d39f46611f4ebeb69edc567c1f4e6b6

Patch
Kernel Git
https://git.kernel.org/stable/c/b3568347c51c46e2cabc356bc34676df98296619

Patch
Kernel Git
https://git.kernel.org/stable/c/bf4d66d72e4a9e268c1012c331ce9eaedb5e2086

Patch
Kernel Git
https://git.kernel.org/stable/c/dbbd328cf58261ca239756fe1c0d10c9518d3399

Patch
Kernel Git
https://git.kernel.org/stable/c/eac3361e3d5dd8067b3258c69615888eb45e9f25

Patch

Details

CVE ID CVE-2026-43379

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-05-08

Modified 2026-05-19

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43379?

CVE-2026-43379 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 6.6.32 onward and has been patched in 6.6.130, 6.12.78, 6.18.19 and others. CVE-2026-43379 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43379?

CVE-2026-43379 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-43379?

Yes. CVE-2026-43379 has been patched. Fixed versions include 6.6.130, 6.12.78, 6.18.19 and others. If you are running Linux kernel 6.6.32 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-43379 actively exploited?

No. CVE-2026-43379 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.