What is CVE-2026-45889?

CVE-2026-45889 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, classified as a Divide By Zero flaw (CWE-369), affecting Linux kernel versions from 6.18 onward and patched in 6.18.14, 6.19.4 and 7.0. CVE-2026-45889 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-45889?

CVE-2026-45889 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-45889?

Yes, CVE-2026-45889 has been patched. Fixed versions include 6.18.14, 6.19.4 and 7.0. If you are running Linux kernel 6.18 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-45889 actively exploited?

CVE-2026-45889 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Divide By Zero (CWE-369)?

The product divides a value by zero, causing a crash or unexpected behaviour. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/369.html

CVE-2026-45889

Medium

In the Linux kernel, the following vulnerability has been resolved: mptcp: do not account for OoO in mptcp_rcvbuf_grow() MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2]. Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated. This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops.

Package Linux Kernel

Published 2026-05-27

Last modified 2026-06-25

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-369

CVE-2026-45889 is a Divide By Zero vulnerability

What is Divide By Zero?

The product divides a value by zero, causing a crash or unexpected behaviour. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.18 and later are affected. Fixed in 6.18.14, 6.19.4, 7.0 and their respective stable series.

Affected from

≥ 6.18

Fixed in

✓ 6.18.14 6.18.x ✓ 6.19.4 6.19.x ✓ 7.0

References

3 total

Kernel Git
https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136

Patch
Kernel Git
https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587

Patch
Kernel Git
https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79

Patch

Details

CVE ID CVE-2026-45889

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-05-27

Modified 2026-06-25

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-45889?

CVE-2026-45889 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a Divide By Zero flaw (CWE-369) . It affects Linux kernel versions from 6.18 onward and has been patched in 6.18.14, 6.19.4 and 7.0. CVE-2026-45889 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-45889?

CVE-2026-45889 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-45889?

Yes. CVE-2026-45889 has been patched. Fixed versions include 6.18.14, 6.19.4 and 7.0. If you are running Linux kernel 6.18 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-45889 actively exploited?

No. CVE-2026-45889 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.