What is CVE-2026-89775?

CVE-2026-89775 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.3 out of 10, affecting Linux kernel versions from 6.16 onward and patched in 6.18.51, 7.2.5 and 7.3-rc1. CVE-2026-89775 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-89775?

CVE-2026-89775 has a CVSS score of 9.3 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Is there a patch available for CVE-2026-89775?

Yes, CVE-2026-89775 has been patched. Fixed versions include 6.18.51, 7.2.5 and 7.3-rc1. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-89775 actively exploited?

CVE-2026-89775 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-89775

Critical

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation Computing the effects of a TLB invalidation involves looking at the size of the mapping cached by the TLB. For S1 mappings such as VNCR, this is deducted from the combination of the base granule size and the mapping level. However, this implies that the S1 MMU is *on*. When the MMU is off, we indicate this with the level being set to a "creative" value of -127 (S1_MMU_DISABLED). This ends-up being misinterpreted by pgshift_level_to_ttl() as it doesn't handle negative levels at all (the level is immediately cast to a u8 and only the bottom two bits considered), leading to an invalidation size of 0. Not helpful. Tidy-up pgshift_level_to_ttl() to handle these negative levels, and ttl_to_size() to always return SZ_1G when no valid TTL is present. This allows the removal of open-coded checks for similar situations. Note that the check for a negative value not explicitely checking for S1_MMU_DISABLED is deliberate, so that actual negative levels introduced with LVA2 and D128 can take the same path if we ever support them.

Package Linux Kernel

Published 2026-09-16

Last modified 2026-09-16

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.3

out of 10

Critical

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.16 and later are affected. Fixed in 6.18.51, 7.2.5, 7.3-rc1 and their respective stable series.

Affected from

≥ 6.16

Fixed in

✓ 6.18.51 6.18.x ✓ 7.2.5 7.2.x ✓ 7.3-rc1

References

4 total

Kernel Git
https://git.kernel.org/stable/c/1c9fca34b9625a67a7f1a03c8604f3df760c6c49
Kernel Git
https://git.kernel.org/stable/c/8053393680d4fa3eb962667d2be95dd39f0940e5
Kernel Git
https://git.kernel.org/stable/c/be54a70067c7dbe1381157e8a238fa4b16ea9c05
Openwall
http://www.openwall.com/lists/oss-security/2026/09/16/14

Details

CVE ID CVE-2026-89775

Severity Critical

CVSS score 9.3 / 10

CVSS version 3.1

Published 2026-09-16

Modified 2026-09-16

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-89775?

CVE-2026-89775 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.3 out of 10 . It affects Linux kernel versions from 6.16 onward and has been patched in 6.18.51, 7.2.5 and 7.3-rc1. CVE-2026-89775 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-89775?

CVE-2026-89775 has a CVSS score of 9.3 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
Is there a patch available for CVE-2026-89775?

Yes. CVE-2026-89775 has been patched. Fixed versions include 6.18.51, 7.2.5 and 7.3-rc1. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-89775 actively exploited?

No. CVE-2026-89775 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.