VulnerabilityPublished 17 Sep 2026Updated 30 Oct 2026

CVE-2026-90232: Linux kernel · amt: Don't support cross-netns setup.

Source GCVE Database

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Authoritative record:CVE-2026-90232· Medium

Not known to be exploited · fixed in e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 18:33 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06, e1dc0af719a2566ae7ccb82c0a11f70aa54908e9, a457ff1189f22c2f15f69df55dc910b8b6d7a77d +3

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-7h9j-j2h3-3xhw

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06	Fixed in e99ecc3046ea5f5c6b5e1f8b4ef854c6c6998e06
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < e1dc0af719a2566ae7ccb82c0a11f70aa54908e9	Fixed in e1dc0af719a2566ae7ccb82c0a11f70aa54908e9
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < a457ff1189f22c2f15f69df55dc910b8b6d7a77d	Fixed in a457ff1189f22c2f15f69df55dc910b8b6d7a77d
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < 569eb11f0990849ba48706a2bfa743273707e254	Fixed in 569eb11f0990849ba48706a2bfa743273707e254
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < 5ebaad6cf2a639afbf0b265f9a7d1fb6f656a37e	Fixed in 5ebaad6cf2a639afbf0b265f9a7d1fb6f656a37e
LinuxLinux	Affected ≥ b9022b53adad88fd6cf2b9718c9e498504f3e1dd, < 2a5a578d2e13d2dd6c1b272be7cfa0a6dd64552c	Fixed in 2a5a578d2e13d2dd6c1b272be7cfa0a6dd64552c

AI-suggested

The vulnerability is addressed by forbidding cross-network namespace setups for AMT devices in the Linux kernel. Users should update to a Linux kernel version that includes this fix. Avoid configuring AMT devices across network namespaces until the fix is applied.

Description

A vulnerability in the Linux kernel's AMT driver involves improper handling of cross-network namespace (netns) setups. Specifically, when a lower network device is unregistered, the AMT device event handler attempts to unregister its upper AMT device but only looks up upper devices within the same netns. This leads to issues if the AMT device is created on a lower device in a different netns, causing the system to hang during device removal. The fix forbids cross-netns setups for AMT devices to prevent this problem.

Impact

This vulnerability can cause the Linux kernel to hang during network device removal operations involving AMT devices configured across different network namespaces. This can lead to system instability or denial of service conditions on affected systems.

Summary

The Linux kernel AMT driver had a flaw where amt_device_event() would try to unregister an upper AMT device only within the lower device's network namespace (netns). If an AMT device was created on a lower device in a different netns, removing the lower device caused a kernel warning and a hang due to waiting for devices to become free. The cross-netns setup appears unintentional, as amt_link_setup() sets the device's netns as immutable and iproute2 fails to create cross-netns AMT devices. The resolution was to forbid cross-netns setups rather than support them. A separate fix is needed for the issue of unregistering only a single upper device.

References

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