What is CVE-2026-90234?

CVE-2026-90234 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, affecting Linux kernel versions from 4.0 onward and patched in 7.2.6 and 7.3-rc1. CVE-2026-90234 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-90234?

CVE-2026-90234 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-2026-90234?

Yes, CVE-2026-90234 has been patched. Fixed versions include 7.2.6 and 7.3-rc1. If you are running Linux kernel 4.0 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-90234 actively exploited?

CVE-2026-90234 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-90234

High

In the Linux kernel, the following vulnerability has been resolved: NFS: Return a delegation the client fails to record When an NFS server grants a delegation in an OPEN reply, nfs_inode_set_delegation() records it on the client. However, three of its error flows return without sending DELEGRETURN. A delegation can be relinquished only by DELEGRETURN (RFC 8881 Section 20.2.4), so dropping one silently leaves the server believing the client still holds it. If the server happens to recall that delegation, the client answers CB_RECALL with NFS4ERR_BADHANDLE because it has no record of the stateid. The server revokes the delegation and moves it onto its cl_revoked list, because the client never sends the FREE_STATEID that would drain it. Every subsequent SEQUENCE reply then carries SEQ4_STATUS_RECALLABLE_STATE_REVOKED, and the client's state manager loops issuing TEST_STATEID across its delegations without ever clearing the condition. The window is easy to reach now that a server offers a write delegation on any write OPEN: a delegation recalled for one opener races a re-open that the server answers with a fresh write delegation. Instead of dropping it, hand the delegation back during these error flows.

Package Linux Kernel

Published 2026-09-17

Last modified 2026-09-18

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 4.0 and later are affected. Fixed in 7.2.6, 7.3-rc1 and their respective stable series.

Affected from

≥ 4.0

Fixed in

✓ 7.2.6 7.2.x ✓ 7.3-rc1

References

2 total

Details

CVE ID CVE-2026-90234

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2026-09-17

Modified 2026-09-18

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-90234?

CVE-2026-90234 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 4.0 onward and has been patched in 7.2.6 and 7.3-rc1. CVE-2026-90234 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-90234?

CVE-2026-90234 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-2026-90234?

Yes. CVE-2026-90234 has been patched. Fixed versions include 7.2.6 and 7.3-rc1. If you are running Linux kernel 4.0 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-90234 actively exploited?

No. CVE-2026-90234 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.