CVE-2026-64123

Kernel memory disclosure or crash via HSR race

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in the Linux Kernel HSR subsystem allows local users to read kernel memory or crash the host during HSR teardown. RTM_DELLINK uses list_del() and immediately frees hsr_node entries while RCU-protected node-list and status readers retain pointers. Exploitation requires CAP_NET_ADMIN and a configured HSR interface; the demonstrated read copies a MAC-address field from freed memory.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 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.

Book a demo

Summary

What happened

Use-after-free in the Linux Kernel HSR subsystem allows local users to read kernel memory or crash the host during HSR teardown. RTM_DELLINK uses list_del() and immediately frees hsr_node entries while RCU-protected node-list and status readers retain pointers. Exploitation requires CAP_NET_ADMIN and a configured HSR interface; the demonstrated read copies a MAC-address field from freed memory.

The record

CVE
CVE-2026-64123
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=08523d5a2f4a9e4202e00d282c164d453cabe2d2
  2. Affected versionversion=5.2.12 <5.3
  3. Affected versionversion=5.3
  4. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <0ea70fb46940620848c08d9d399455c9e82fecdb
  5. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <6324423a8e6591f41a16c09a8f9a84e554ac147c
  6. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <7713f4aafb577ff49fa67f0488d9c7dddc64d6ce
  7. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b
  8. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <8c3af18bb0d7c921a5219194037509463eb2ffde
  9. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <aaec7096f9961eb223b5b149abe9495525c205d9
  10. Affected versionversion=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <c5580114e0492bcd2e0a37613ed4c311e3fa3d4d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=08523d5a2f4a9e4202e00d282c164d453cabe2d2; version=5.2.12 <5.3; version=5.3; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <0ea70fb46940620848c08d9d399455c9e82fecdb; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <6324423a8e6591f41a16c09a8f9a84e554ac147c; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <7713f4aafb577ff49fa67f0488d9c7dddc64d6ce; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <8c3af18bb0d7c921a5219194037509463eb2ffde; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <aaec7096f9961eb223b5b149abe9495525c205d9; version=b9a1e627405d68d475a3c1f35e685ccfb5bbe668 <c5580114e0492bcd2e0a37613ed4c311e3fa3d4d

Published CVSS scores

7.8Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

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

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo