What is the CVSS score of CVE-2026-64166?

CVE-2026-64166 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2026-64166?

Yes, a patch is available for CVE-2026-64166. Update the affected software to the latest version immediately.

Linux Kernel CVE-2026-64166

EUVD-2026-45851 MEDIUM

NULL Pointer Dereference (CWE-476)

2026-07-19 Linux

GHSA-hfhw-j953-vcq4

Denial Of Service Linux Null Pointer Dereference Red Hat Suse

5.5

CVSS 3.1 · NVD

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Obtain kernel module loading rights
Delivery

Craft FF-A driver omitting id_table
Exploit

Load driver to trigger bus registration
Execution

Bus match callback dereferences NULL id_table
Impact

Kernel panic causes denial of service

Vulnerability Assessment

Weakness	CWE CWE-476 OWASP Top 10:2025 A10:2025 - Mishandling of Exceptional Conditions ASVS 5.0 V16 - Security Logging and Error Handling Null pointer safety, defensive checks MITRE ATT&CK 1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Exploitation requires local access to the target system and CAP_SYS_MODULE capability - typically root or an equivalent privileged account - to load the kernel module that triggers the bug. The arm_ffa subsystem must be active, which is limited to ARM hardware platforms implementing the Firmware Framework for Armv8-A protocol (TrustZone-capable devices). The fault is triggered specifically by registering an FF-A client driver without supplying the id_table field. Standard unprivileged user-space processes cannot reach this code path. Non-ARM systems (x86, RISC-V, etc.) are entirely unexposed regardless of kernel version.
Impact	Real-world risk is substantially lower than the raw CVSS availability impact implies. Exploitation requires local access and kernel module loading rights (CAP_SYS_MODULE, restricted to root or equivalent on hardened distributions), making this effectively a privileged local denial-of-service rather than an unprivileged attack. The CVSS-assigned PR:L metric may overstate attacker reach - the Linux security model constrains module loading to privileged actors on typical enterprise configurations, a discrepancy worth verifying against the specific deployment. EPSS at 0.17% in the 6th percentile corroborates very low exploitation interest, and the absence from the CISA KEV catalog confirms no confirmed active exploitation. No POC has been identified. Even a mid-sized municipal IT team in malbork running ARM server infrastructure would realistically encounter this only through accidental deployment of a malformed FF-A client driver rather than targeted attack. Additionally, the arm_ffa subsystem is only present and active on ARM hardware that implements FF-A support, which limits the exposure universe to TrustZone-capable ARM platforms.
Exploit ScenarioDerived	A local actor with CAP_SYS_MODULE privilege loads a crafted or defective ARM FF-A client driver that omits the mandatory id_table pointer. When the arm_ffa bus attempts device-to-driver matching, the match callback dereferences the NULL id_table pointer, triggering a kernel oops or panic and taking the system offline. No public exploit code has been identified at time of analysis.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 13, 2026

NULL pointer dereference in the Linux kernel's ARM Firmware Framework for Armv8-A (arm_ffa) bus driver allows a local actor with kernel module loading rights to crash the host system. The bus match callback unconditionally dereferences the id_table pointer of any registering FF-A client driver; a driver that omits id_table triggers an immediate kernel panic, producing a denial-of-service condition. EPSS at 0.17% (6th percentile) and absence from the CISA KEV catalog indicate no public exploit and negligible observed exploitation activity.

RemediationAI

Upgrade to a patched kernel release matching your active stable branch: 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11, or 7.1. Upstream stable-tree commits for each branch are available at https://git.kernel.org/stable/c/f98f131256beaddd51ad468e95d90d857fef12bf and related commits (bc499d1a, adfff93d, 34f59211, 820245d8, 198f6c86, 0a5e6950). Ubuntu users should apply the update from USN-8575-1 at https://ubuntu.com/security/notices/USN-8575-1. As a compensating control on systems that cannot be patched immediately, set kernel.modules_disabled=1 via sysctl to prevent further module loading after boot - note this is irreversible without reboot and will block all subsequent module loads, which may impact runtime management of drivers and filesystems. Systems not using ARM hardware with FF-A support require no remediation action regardless of kernel version.

Affected VersionsENISA

Linux patch: 5.15.209

Linux patch: 7.1

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <198f6c86d508ed562f07dc00276cac6dbb5dd3bf

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <adfff93d08a2e12ecf2a1eba272d18bc749f13c0

Linux 5.14

Linux patch: 6.18.34

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <0a5e695095c557d2380131b613dea4e8d90371be

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <34f59211984f66788390e7469f3e99d3796db4a8

Linux patch: 0

Linux patch: 6.6.142

Linux patch: 7.0.11

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <bc499d1acddbb75b5b4bce05f5296dd8ef9611fd

Linux patch: 6.12.92

Linux patch: 6.1.175

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <820245d86ce58898fb48b4fefc77d0cafc02801d

Linux 92743071464fca5acbbe812d9a0d88de3eaaad36 <f98f131256beaddd51ad468e95d90d857fef12bf

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The ARM Firmware Framework for Armv8-A (FF-A) is a protocol enabling isolated communication between the Rich Execution Environment (REE) and the Secure Partition Manager (SPM) in ARM TrustZone-based systems. The Linux kernel exposes this as the arm_ffa bus, where registered client drivers are matched to devices via a bus-level match callback that iterates the driver's id_table. CWE-476 (NULL Pointer Dereference) arises because this callback dereferences id_table without first confirming it is non-NULL. If a conformant contract is violated - a client driver is registered without supplying id_table - the kernel faults immediately during bus matching. The fix enforces the contract at driver registration time rather than at match time, eliminating the fault surface. Affected CPE: cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:* across the arm_ffa subsystem introduced at commit 92743071464f.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM

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

vuln.today AI 4.4 MEDIUM

Registering a kernel driver requires CAP_SYS_MODULE (effectively root), warranting PR:H over NVD's PR:L; impact is availability-only via kernel panic.

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

4.0 AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SUSE MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVSS changed

Aug 13, 2026 - 15:37 NVD

5.5 (MEDIUM)

Patch available

Jul 19, 2026 - 17:03 EUVD

CVE Published

Jul 19, 2026 - 15:40 cve.org

UNKNOWN (no severity yet)

CVE Published

Jul 19, 2026 - 15:40 nvd

MEDIUM 5.5

DescriptionNVD

In the Linux kernel, the following vulnerability has been resolved:

firmware: arm_ffa: Check for NULL FF-A ID table while driver registration

The bus match callback assumes that every FF-A driver provides an id_table and dereferences it unconditionally. Enforce that contract at registration time so a buggy client driver cannot crash the bus during match.

Threat Intelligence Overview

EPSS Score

0.2%

Top 94% exploitable

Prevalence

Medium

ARM-specific subsystem; absent on x86 and non-FF-A hardware

Data Quality

5 sources

Confidence: Medium

EUVD

NVD

CVE.org

EPSS Vendor

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.2%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Defer

Exploitation· derived

None

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +28

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Null Pointer Dereference MEDIUM

A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Same weakness CWE-476 – NULL Pointer Dereference

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CVE-2016-0742 HIGH

7.5

CVE-2014-3470 MEDIUM

4.3

CVE-2020-1967 HIGH POC

7.5

CVE-2017-3730 HIGH POC

7.5

CVE-2017-3169 CRITICAL POC

9.8

CVE-2016-4957 HIGH

7.5

CVE-2021-3449 MEDIUM

5.9

CVE-2015-3194 HIGH

7.5

Same technique Denial Of Service

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CVE-2015-5119 CRITICAL POC

9.8

CVE-2011-2462 CRITICAL POC

9.8

CVE-2011-0611 HIGH POC

8.8

CVE-2012-1889 HIGH POC

8.8

CVE-2012-0507 CRITICAL POC

9.8

CVE-2014-1761 HIGH POC

7.8

CVE-2015-5122 CRITICAL POC

9.8

CVE-2011-0609 HIGH POC

7.8

Vendor StatusVendor

SUSE

Severity: Moderate

Product	Status
SUSE Linux Enterprise Desktop 15 SP7	Not-Affected
SUSE Linux Enterprise Desktop 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0	Not-Affected

References

Advisories & patches

ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-64166 ADVISORY https://seclists.org/oss-sec/2026/q3/230 ADVISORY https://ubuntu.com/security/notices/USN-8575-1 ADVISORY https://vuldb.com/vuln/380317 REF https://git.kernel.org/stable/c/0a5e695095c557d2380131b613dea4e8d90371be REF https://git.kernel.org/stable/c/198f6c86d508ed562f07dc00276cac6dbb5dd3bf REF https://git.kernel.org/stable/c/34f59211984f66788390e7469f3e99d3796db4a8 REF https://git.kernel.org/stable/c/820245d86ce58898fb48b4fefc77d0cafc02801d REF https://git.kernel.org/stable/c/adfff93d08a2e12ecf2a1eba272d18bc749f13c0 REF https://git.kernel.org/stable/c/bc499d1acddbb75b5b4bce05f5296dd8ef9611fd REF https://git.kernel.org/stable/c/f98f131256beaddd51ad468e95d90d857fef12bf

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