What is CVE-2026-64381?

CVE-2026-64381 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, classified as a Out-of-bounds Write flaw (CWE-787), affecting Linux kernel versions from 4.19 onward and patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64381 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64381?

CVE-2026-64381 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-64381?

Yes, CVE-2026-64381 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 4.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64381 actively exploited?

CVE-2026-64381 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Out-of-bounds Write (CWE-787)?

The product writes data past the end or before the beginning of the intended buffer. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/787.html

CVE-2026-64381

High

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix next buffer leak in receive_encrypted_standard() receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked. Move the MAX_COMPOUND check before allocating next_buffer.

Package Linux Kernel

Published 2026-07-25

Last modified 2026-09-08

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Weakness type

CWE-787

CVE-2026-64381 is a Out-of-bounds Write vulnerability

What is Out-of-bounds Write?

The product writes data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 4.19 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

≥ 4.19

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/07e0ab81df1790afa35732a4e8e07ff831b29008

Patch
Kernel Git
https://git.kernel.org/stable/c/1c6267a1d5cf4c73b656f8181b310cbbb3e4767b

Patch
Kernel Git
https://git.kernel.org/stable/c/297243e365fc9fe2f8e9b7dd535a65d922cd108b

Patch
Kernel Git
https://git.kernel.org/stable/c/67097772df7791c53d608f04bd31c676ccf79b83

Patch
Kernel Git
https://git.kernel.org/stable/c/68fc0b6cc03ca58060c0f36454e169f5fe258974

Patch

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-64381

Severity High

CVSS score 7.8 / 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-2026-64381?

CVE-2026-64381 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Out-of-bounds Write flaw (CWE-787) . It affects Linux kernel versions from 4.19 onward and has been patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64381 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64381?

CVE-2026-64381 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-64381?

Yes. CVE-2026-64381 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 4.19 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64381 actively exploited?

No. CVE-2026-64381 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.