What is CVE-2026-64380?

CVE-2026-64380 is a High severity Linux kernel vulnerability with a CVSS score of 8.2 out of 10, affecting Linux kernel versions from 5.7 onward and patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64380 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64380?

CVE-2026-64380 has a CVSS score of 8.2 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.

Is there a patch available for CVE-2026-64380?

Yes, CVE-2026-64380 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 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-2026-64380 actively exploited?

CVE-2026-64380 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64380

High

In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

Package Linux Kernel

Published 2026-07-25

Last modified 2026-09-08

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

8.2

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.7 and later are affected. Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 and their respective stable series.

Affected from

≥ 5.7

Fixed in

✓ 5.10.261 5.10.x ✓ 5.15.212 5.15.x ✓ 6.1.178 6.1.x ✓ 6.6.145 6.6.x ✓ 6.12.96 6.12.x ✓ 6.18.39 6.18.x ✓ 7.1.4 7.1.x ✓ 7.2

References

8 total

Kernel Git
https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da

Patch
Kernel Git
https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b

Patch
Kernel Git
https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61

Patch
Kernel Git
https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59

Patch
Kernel Git
https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4

Patch

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-64380

Severity High

CVSS score 8.2 / 10

CVSS version 3.1

Published 2026-07-25

Modified 2026-09-08

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64380?

CVE-2026-64380 is a High severity Linux kernel vulnerability with a CVSS score of 8.2 out of 10 . It affects Linux kernel versions from 5.7 onward and has been patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64380 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64380?

CVE-2026-64380 has a CVSS score of 8.2 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H.
Is there a patch available for CVE-2026-64380?

Yes. CVE-2026-64380 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 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-2026-64380 actively exploited?

No. CVE-2026-64380 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.