What is CVE-2026-31409?

CVE-2026-31409 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10, affecting Linux kernel versions from 5.15 onward and patched in 5.15.209, 6.1.167, 6.6.130 and others. CVE-2026-31409 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-31409?

CVE-2026-31409 has a CVSS score of 8.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-31409?

Yes, CVE-2026-31409 has been patched. Fixed versions include 5.15.209, 6.1.167, 6.6.130 and others. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-31409 actively exploited?

CVE-2026-31409 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-31409

High

In the Linux kernel, the following vulnerability has been resolved: ksmbd: unset conn->binding on failed binding request When a multichannel SMB2_SESSION_SETUP request with SMB2_SESSION_REQ_FLAG_BINDING fails ksmbd sets conn->binding = true but never clears it on the error path. This leaves the connection in a binding state where all subsequent ksmbd_session_lookup_all() calls fall back to the global sessions table. This fix it by clearing conn->binding = false in the error path.

Package Linux Kernel

Published 2026-04-06

Last modified 2026-06-01

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

8.8

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.15 and later are affected. Fixed in 5.15.209, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0 and their respective stable series.

Affected from

≥ 5.15

Fixed in

✓ 5.15.209 5.15.x ✓ 6.1.167 6.1.x ✓ 6.6.130 6.6.x ✓ 6.12.78 6.12.x ✓ 6.18.20 6.18.x ✓ 6.19.10 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-31409 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/282343cf8a4a5a3603b1cb0e17a7083e4a593b03
Patch
Kernel patch commit
https://git.kernel.org/stable/c/6260fc85ed1298a71d24a75d01f8b2e56d489a60
Patch
Kernel patch commit
https://git.kernel.org/stable/c/6ebef4a220a1ebe345de899ebb9ae394206fe921
Patch

7 patch commits total View all on NVD

Details

CVE ID CVE-2026-31409

Severity High

CVSS score 8.8 / 10

CVSS version 3.1

Published 2026-04-06

Modified 2026-06-01

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-31409?

CVE-2026-31409 is a High severity Linux kernel vulnerability with a CVSS score of 8.8 out of 10 . It affects Linux kernel versions from 5.15 onward and has been patched in 5.15.209, 6.1.167, 6.6.130 and others. CVE-2026-31409 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-31409?

CVE-2026-31409 has a CVSS score of 8.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-31409?

Yes — CVE-2026-31409 has been patched. Fixed versions include 5.15.209, 6.1.167, 6.6.130 and others. If you are running Linux kernel 5.15 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-31409 actively exploited?

No — CVE-2026-31409 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.