What is CVE-2026-64186?

CVE-2026-64186 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10, classified as a Out-of-bounds Read flaw (CWE-125), affecting Linux kernel versions from 6.17 onward and patched in 6.18.34, 7.0.11 and 7.1. CVE-2026-64186 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64186?

CVE-2026-64186 has a CVSS score of 7.1 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.

Is there a patch available for CVE-2026-64186?

Yes, CVE-2026-64186 has been patched. Fixed versions include 6.18.34, 7.0.11 and 7.1. If you are running Linux kernel 6.17 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64186 actively exploited?

CVE-2026-64186 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Out-of-bounds Read (CWE-125)?

The product reads data past the end or before the beginning of the intended buffer. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/125.html

CVE-2026-64186

High

In the Linux kernel, the following vulnerability has been resolved: iommu/amd: Remove latent out-of-bounds access in IOMMU debugfs In iommu_mmio_write() and iommu_capability_write(), the variables dbg_mmio_offset and dbg_cap_offset are declared as int. However, they are populated using kstrtou32_from_user(). If a user provides a sufficiently large value, it can become a negative integer. Prior to this patch, the AMD IOMMU debugfs implementation was already protected by different mechanisms. 1. #define OFS_IN_SZ 8 ensures the user string <= 8 bytes, so e.g. 0xffffffff isn't a valid input. if (cnt > OFS_IN_SZ) return -EINVAL; 2. Implicit type promotion in iommu_mmio_write(), dbg_mmio_offset is int and iommu->mmio_phys_end is u64 if (dbg_mmio_offset > iommu->mmio_phys_end - sizeof(u64)) return -EINVAL; 3. The show handlers would currently catch the negative number and refuse to perform the read. Replace kstrtou32_from_user() with kstrtos32_from_user() to parse the input, and check for negative values to explicitly prevent out-of-bounds memory accesses directly in iommu_mmio_write() and iommu_capability_write().

Package Linux Kernel

Published 2026-07-19

Last modified 2026-08-11

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.1

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-125

CVE-2026-64186 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

The product reads data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.17 and later are affected. Fixed in 6.18.34, 7.0.11, 7.1 and their respective stable series.

Affected from

≥ 6.17

Fixed in

✓ 6.18.34 6.18.x ✓ 7.0.11 7.0.x ✓ 7.1

References

3 total

Kernel Git
https://git.kernel.org/stable/c/488d2c76bd9f78433a70690d1054bfae3d39a407

Patch
Kernel Git
https://git.kernel.org/stable/c/62f9dfbf1aceae88b03c5ca08f7d36e943939dec

Patch
Kernel Git
https://git.kernel.org/stable/c/8dfd3d8d74435344ee8dc9237596959c8b2a6cbe

Patch

Details

CVE ID CVE-2026-64186

Severity High

CVSS score 7.1 / 10

CVSS version 3.1

Published 2026-07-19

Modified 2026-08-11

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64186?

CVE-2026-64186 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . It affects Linux kernel versions from 6.17 onward and has been patched in 6.18.34, 7.0.11 and 7.1. CVE-2026-64186 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64186?

CVE-2026-64186 has a CVSS score of 7.1 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.
Is there a patch available for CVE-2026-64186?

Yes. CVE-2026-64186 has been patched. Fixed versions include 6.18.34, 7.0.11 and 7.1. If you are running Linux kernel 6.17 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64186 actively exploited?

No. CVE-2026-64186 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.