What is CVE-2026-31537?

CVE-2026-31537 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 5.15 onward and patched in 6.18.11, 6.19.1 and 7.0. CVE-2026-31537 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-31537?

CVE-2026-31537 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-2026-31537?

Yes, CVE-2026-31537 has been patched. Fixed versions include 6.18.11, 6.19.1 and 7.0. 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-2026-31537 actively exploited?

CVE-2026-31537 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-31537

Medium

In the Linux kernel, the following vulnerability has been resolved: smb: server: make use of smbdirect_socket.send_io.bcredits It turns out that our code will corrupt the stream of reassabled data transfer messages when we trigger an immendiate (empty) send. In order to fix this we'll have a single 'batch' credit per connection. And code getting that credit is free to use as much messages until remaining_length reaches 0, then the batch credit it given back and the next logical send can happen.

Package Linux Kernel

Published 2026-04-24

Last modified 2026-04-28

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 5.15 and later are affected. Fixed in 6.18.11, 6.19.1, 7.0 and their respective stable series.

Affected from

≥ 5.15

Fixed in

✓ 6.18.11 6.18.x ✓ 6.19.1 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-31537 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/34abd408c8ba24d7c97bd02ba874d8c714f49db1
Patch
Kernel patch commit
https://git.kernel.org/stable/c/5ef18a2e66f2f33fdac64437bddfb9fe6389fdc7
Patch
Kernel patch commit
https://git.kernel.org/stable/c/79242e7b6bc63efec28b7c235bc320806afce6c0
Patch

Details

CVE ID CVE-2026-31537

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-04-24

Modified 2026-04-28

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-31537?

CVE-2026-31537 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.15 onward and has been patched in 6.18.11, 6.19.1 and 7.0. CVE-2026-31537 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-31537?

CVE-2026-31537 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-2026-31537?

Yes — CVE-2026-31537 has been patched. Fixed versions include 6.18.11, 6.19.1 and 7.0. 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-2026-31537 actively exploited?

No — CVE-2026-31537 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.