CVE-2026-93097 cxl/mbox: Break poison list loop on an empty payload
A malicious CXL device can cause a kernel hang by returning empty poison lists, blocking system operations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93097?
CVE-2026-93097 is a denial of service vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
cxl/mbox: Break poison list loop on an empty payload
A device that returns count == 0 with CXL_POISON_FLAG_MORE set on every iteration never advances nr_records, so the max_errors guard never trips and the do/while loops forever while holding poison.mutex. That hangs the sysfs-triggered scan thread and blocks all subsequent poison operations on the device. The existing "Protect against an uncleared _FLAG_MORE" guard was intended to bound a misbehaving device but does not cover the count == 0 case.
Stop the loop on an empty payload so a malfunctioning or malicious device cannot wedge the poison scan.
Which versions are affected by CVE-2026-93097?
How do I fix CVE-2026-93097?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93097 being exploited?
There is no known exploitation of CVE-2026-93097 in the wild and no public exploit code.
Sources
Also known as AZL-102980, BELL-CVE-2026-93097, DEBIAN-CVE-2026-93097, GHSA-x7w4-f354-q3xf, UBUNTU-CVE-2026-93097.