CVE-2026-80990 net: thunderbolt: Release the Rx HopID that was handed out on mismatch
A resource leak in the Linux kernel Thunderbolt network driver allows attackers to exhaust HopIDs, causing denial of service.
- 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-2026-80990?
CVE-2026-80990 is a denial of service vulnerability in Linux, published on 11 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:
net: thunderbolt: Release the Rx HopID that was handed out on mismatch
tb_xdomain_alloc_in_hopid() passes the wanted HopID to ida_alloc_range() as the lower bound, so a taken id is not an error there: the allocator returns the next free one above it. tbnet_connected_work() asks for the peer's transmit path, treats any other id as a failure and returns without releasing what it got, so that allocation stays live for the rest of the XDomain connection with nothing left holding a reference to it.
Release the id when it is not the one we asked for, the same way the error unwind at the end of the function releases the expected one.
Which versions are affected by CVE-2026-80990?
How do I fix CVE-2026-80990?
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-2026-80990 being exploited?
There is no known exploitation of CVE-2026-80990 in the wild and no public exploit code.
Sources
Also known as AZL-100662, BELL-CVE-2026-80990, DEBIAN-CVE-2026-80990, GHSA-33rp-ch35-2jf6, UBUNTU-CVE-2026-80990.