What is CVE-2026-89630?

CVE-2026-89630 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.1 out of 10, affecting Linux kernel versions from 6.19 onward and patched in 7.2.4 and 7.3-rc1. CVE-2026-89630 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89630?

CVE-2026-89630 has a CVSS score of 9.1 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:N/A:H.

Is there a patch available for CVE-2026-89630?

Yes, CVE-2026-89630 has been patched. Fixed versions include 7.2.4 and 7.3-rc1. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89630 actively exploited?

CVE-2026-89630 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89630

Critical

In the Linux kernel, the following vulnerability has been resolved: smb: client: restore the data_offset bound in is_valid_oplock_break() Commit 83bfbd0bb902 ("cifs: Remove the RFC1002 header from smb_hdr") changed the quantity this bound is measured against. It used to be srv->total_read minus the 4-byte RFC1002 preamble that total_read then included, so it was the SMB message length. The same commit stopped counting the preamble, and the mechanical substitution to srv->total_read - srv->pdu_size left an expression that is identically zero: standard_receive3() reads MID_HEADER_SIZE() bytes and then exactly pdu_length - MID_HEADER_SIZE() more, adding both to total_read. len is therefore 0, the subtraction below it wraps, and no __u32 DataOffset can exceed the result, so the check from commit 097f5863b1a0 ("cifs: read overflow in is_valid_oplock_break()") no longer rejects anything. Use total_read, which is now the message length on its own.

Package Linux Kernel

Published 2026-09-11

Last modified 2026-09-13

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.1

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.19 and later are affected. Fixed in 7.2.4, 7.3-rc1 and their respective stable series.

Affected from

≥ 6.19

Fixed in

✓ 7.2.4 7.2.x ✓ 7.3-rc1

References

2 total

Details

CVE ID CVE-2026-89630

Severity Critical

CVSS score 9.1 / 10

CVSS version 3.1

Published 2026-09-11

Modified 2026-09-13

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89630?

CVE-2026-89630 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.1 out of 10 . It affects Linux kernel versions from 6.19 onward and has been patched in 7.2.4 and 7.3-rc1. CVE-2026-89630 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89630?

CVE-2026-89630 has a CVSS score of 9.1 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:N/A:H.
Is there a patch available for CVE-2026-89630?

Yes. CVE-2026-89630 has been patched. Fixed versions include 7.2.4 and 7.3-rc1. If you are running Linux kernel 6.19 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89630 actively exploited?

No. CVE-2026-89630 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.