What is CVE-2025-40210?

CVE-2025-40210 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, affecting Linux kernel versions from 6.17 onward and patched in 6.17.8 and 6.18. CVE-2025-40210 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40210?

CVE-2025-40210 has a CVSS score of 7.5 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-40210?

Yes, CVE-2025-40210 has been patched. Fixed versions include 6.17.8 and 6.18. If you are running Linux kernel 6.17 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40210 actively exploited?

CVE-2025-40210 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40210

High

In the Linux kernel, the following vulnerability has been resolved: Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND" I've found that pynfs COMP6 now leaves the connection or lease in a strange state, which causes CLOSE9 to hang indefinitely. I've dug into it a little, but I haven't been able to root-cause it yet. However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"). Tianshuo Han also reports a potential vulnerability when decoding an NFSv4 COMPOUND. An attacker can place an arbitrarily large op count in the COMPOUND header, which results in: [ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0 when NFSD attempts to allocate the COMPOUND op array. Let's restore the operation-per-COMPOUND limit, but increased to 200 for now.

Package Linux Kernel

Published 2025-11-21

Last modified 2026-07-30

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.5

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:N/I:N/A:H

Affected versions

Linux kernel versions 6.17 and later are affected. Fixed in 6.17.8, 6.18 and their respective stable series.

Affected from

≥ 6.17

Fixed in

✓ 6.17.8 6.17.x ✓ 6.18

References

2 total

Details

CVE ID CVE-2025-40210

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2025-11-21

Modified 2026-07-30

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-40210?

CVE-2025-40210 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 6.17 onward and has been patched in 6.17.8 and 6.18. CVE-2025-40210 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-40210?

CVE-2025-40210 has a CVSS score of 7.5 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:N/I:N/A:H.
Is there a patch available for CVE-2025-40210?

Yes. CVE-2025-40210 has been patched. Fixed versions include 6.17.8 and 6.18. If you are running Linux kernel 6.17 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40210 actively exploited?

No. CVE-2025-40210 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.