CVE-2026-90306

Local breakpoint denial via unconditional CFI handler

Published Sep 17, 2026 · Updated Sep 21, 2026

Breakpoint mishandling in Linux 6.10 and later affected ARM builds allows local users to prevent delivery of breakpoint type 0x03. The stub hw_breakpoint_cfi_handler() consumes ARM_ENTRY_CFI_BREAKPOINT unconditionally even when kernel CFI is inactive or the breakpoint originates in userspace. The condition is limited to 32-bit ARM kernels containing the introduced code; it denies the affected userspace breakpoint rather than disclosing or modifying data.

CVSS severity3.3
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Breakpoint mishandling in Linux 6.10 and later affected ARM builds allows local users to prevent delivery of breakpoint type 0x03. The stub hw_breakpoint_cfi_handler() consumes ARM_ENTRY_CFI_BREAKPOINT unconditionally even when kernel CFI is inactive or the breakpoint originates in userspace. The condition is limited to 32-bit ARM kernels containing the introduced code; it denies the affected userspace breakpoint rather than disclosing or modifying data.

The record

CVE
CVE-2026-90306
Published
Sep 17, 2026
Updated
Sep 21, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.10
  2. Affected versionversion=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <314f1a6762b5d51b37784ed7dc701d4c3d893703
  3. Affected versionversion=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <8ed9bff906cf8036531d1559f10e82733a52b41f
  4. Affected versionversion=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <da64b150e4b7bee615b33ab21f3137c31ec36922

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.10; version=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <314f1a6762b5d51b37784ed7dc701d4c3d893703; version=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <8ed9bff906cf8036531d1559f10e82733a52b41f; version=c3f89986fde7bb9ccc86a901bf28e1f7d69fc3b3 <da64b150e4b7bee615b33ab21f3137c31ec36922

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started