What is CVE-2025-40297?

CVE-2025-40297 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 5.18 onward and patched in 6.1.159, 6.6.117, 6.12.58 and others. CVE-2025-40297 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40297?

CVE-2025-40297 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-2025-40297?

Yes, CVE-2025-40297 has been patched. Fixed versions include 6.1.159, 6.6.117, 6.12.58 and others. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40297 actively exploited?

CVE-2025-40297 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40297

High

In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix use-after-free due to MST port state bypass syzbot reported[1] a use-after-free when deleting an expired fdb. It is due to a race condition between learning still happening and a port being deleted, after all its fdbs have been flushed. The port's state has been toggled to disabled so no learning should happen at that time, but if we have MST enabled, it will bypass the port's state, that together with VLAN filtering disabled can lead to fdb learning at a time when it shouldn't happen while the port is being deleted. VLAN filtering must be disabled because we flush the port VLANs when it's being deleted which will stop learning. This fix adds a check for the port's vlan group which is initialized to NULL when the port is getting deleted, that avoids the port state bypass. When MST is enabled there would be a minimal new overhead in the fast-path because the port's vlan group pointer is cache-hot. [1] https://syzkaller.appspot.com/bug?extid=dd280197f0f7ab3917be

Package Linux Kernel

Published 2025-12-08

Last modified 2026-07-30

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

Affected versions

Linux kernel versions 5.18 and later are affected. Fixed in 6.1.159, 6.6.117, 6.12.58, 6.17.8, 6.18 and their respective stable series.

Affected from

≥ 5.18

Fixed in

✓ 6.1.159 6.1.x ✓ 6.6.117 6.6.x ✓ 6.12.58 6.12.x ✓ 6.17.8 6.17.x ✓ 6.18

References

5 total

Details

CVE ID CVE-2025-40297

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2025-12-08

Modified 2026-07-30

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-40297?

CVE-2025-40297 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.18 onward and has been patched in 6.1.159, 6.6.117, 6.12.58 and others. CVE-2025-40297 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-40297?

CVE-2025-40297 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-2025-40297?

Yes. CVE-2025-40297 has been patched. Fixed versions include 6.1.159, 6.6.117, 6.12.58 and others. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40297 actively exploited?

No. CVE-2025-40297 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.