CVE-2026-90100

Kernel crash via PEROUT period truncation

Published Sep 17, 2026 · Updated Sep 17, 2026

Divide-by-zero in Linux 6.18 NETC PTP allows local users to crash kernel code via a crafted periodic-output request. net_timer_enable_perout() accepts periods exceeding 32 bits and truncates them to zero, which netc_timer_set_perout_alarm() uses as a divisor when advancing an expired start time. Reachability requires NETC timer hardware and writable PTP-device access; the invalid period also misprograms the FIPER register, with host availability consequences dependent on kernel exception handling.

CVSS severity4.4
Medium
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

Divide-by-zero in Linux 6.18 NETC PTP allows local users to crash kernel code via a crafted periodic-output request. net_timer_enable_perout() accepts periods exceeding 32 bits and truncates them to zero, which netc_timer_set_perout_alarm() uses as a divisor when advancing an expired start time. Reachability requires NETC timer hardware and writable PTP-device access; the invalid period also misprograms the FIPER register, with host availability consequences dependent on kernel exception handling.

The record

CVE
CVE-2026-90100
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=6.18
  2. Affected versionversion=671e266835b8a87d6cc2c6db962de23783405dd8 <08988d1941e180f0ad30d91233cb64f3418ba23c
  3. Affected versionversion=671e266835b8a87d6cc2c6db962de23783405dd8 <51fe3fe0ffec033bd831c71d9bee3dee827e491c
  4. Affected versionversion=671e266835b8a87d6cc2c6db962de23783405dd8 <777dbc9914b2f003f1d44af80c7a4a395c5961b2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.18; version=671e266835b8a87d6cc2c6db962de23783405dd8 <08988d1941e180f0ad30d91233cb64f3418ba23c; version=671e266835b8a87d6cc2c6db962de23783405dd8 <51fe3fe0ffec033bd831c71d9bee3dee827e491c; version=671e266835b8a87d6cc2c6db962de23783405dd8 <777dbc9914b2f003f1d44af80c7a4a395c5961b2

Published CVSS scores

4.4SUSECVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.4Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/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.

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
Privilegesadmin
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