What is CVE-2026-90104?

CVE-2026-90104 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 2.6.31 onward and patched in 7.2.6 and 7.3-rc1. CVE-2026-90104 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-90104?

CVE-2026-90104 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-90104?

Yes, CVE-2026-90104 has been patched. Fixed versions include 7.2.6 and 7.3-rc1. If you are running Linux kernel 2.6.31 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-90104 actively exploited?

CVE-2026-90104 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-90104

Critical

In the Linux kernel, the following vulnerability has been resolved: NFSv4.1: zero referring call lists before decoding decode_cb_sequence_args() allocates csa_rclists with kmalloc_objs(), so each referring_call_list starts uninitialized. decode_rc_list() assigns rcl_refcalls only when rcl_nrefcalls is nonzero. A valid list with zero referring calls therefore leaves the pointer uninitialized, and nfs4_callback_sequence() later passes stale slab contents to kfree(). Allocate csa_rclists with kzalloc_objs() so every rcl_refcalls member is NULL from the beginning, including valid empty referring call lists.

Package Linux Kernel

Published 2026-09-17

Last modified 2026-09-18

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 2.6.31 and later are affected. Fixed in 7.2.6, 7.3-rc1 and their respective stable series.

Affected from

≥ 2.6.31

Fixed in

✓ 7.2.6 7.2.x ✓ 7.3-rc1

References

2 total

Details

CVE ID CVE-2026-90104

Severity Critical

CVSS score 9.8 / 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-2026-90104?

CVE-2026-90104 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 2.6.31 onward and has been patched in 7.2.6 and 7.3-rc1. CVE-2026-90104 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-90104?

CVE-2026-90104 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-90104?

Yes. CVE-2026-90104 has been patched. Fixed versions include 7.2.6 and 7.3-rc1. If you are running Linux kernel 2.6.31 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-90104 actively exploited?

No. CVE-2026-90104 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.