# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100662, BELL-CVE-2026-80990, DEBIAN-CVE-2026-80990, GHSA-33rp-ch35-2jf6, UBUNTU-CVE-2026-80990

## 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.

## Is CVE-2026-80990 being exploited?

There is no known exploitation of CVE-2026-80990 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80990 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-80990 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80990/ (Markdown: https://insights.sbomify.com/CVE-2026-80990/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80990
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80990
- OSV: https://osv.dev/vulnerability/CVE-2026-80990

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80990/
Summaries are generated and may contain mistakes; the official description above is the record.