# CVE-2026-80651: crypto: ccp/sev-dev-tsm - bail out early when pdev->bus is NULL

> A null pointer dereference in the Linux kernel's SEV TSM driver allows local attackers to cause a system crash.

- **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:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-80651, GHSA-m48c-q8rx-qxxm, UBUNTU-CVE-2026-80651

## What is CVE-2026-80651?

CVE-2026-80651 is a vulnerability in Linux, published on 28 Aug 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:

crypto: ccp/sev-dev-tsm - bail out early when pdev->bus is NULL

dsm_create() initially checks pdev->bus when computing segment_id:

	u8 segment_id = pdev->bus ? pci_domain_nr(pdev->bus) : 0;

But the next two lines unconditionally dereference pdev->bus via
pcie_find_root_port() and especially pci_dev_id(pdev), which expands
to PCI_DEVID(dev->bus->number, dev->devfn). If pdev->bus is in fact
NULL, segment_id is initialised to 0 but the very next statement
crashes the kernel.

smatch flags this:

  drivers/crypto/ccp/sev-dev-tsm.c:253 dsm_create() error: we
    previously assumed 'pdev->bus' could be null (see line 251)

Make the NULL handling consistent: if pdev->bus is NULL the device
has no PCI context to work with and SEV TIO setup cannot proceed,
so return -ENODEV before any of the bus-dependent lookups. The
remaining initialisation now runs only on the path where pdev->bus
is known to be valid.

No change for callers where pdev->bus is non-NULL, which is the
only case where dsm_create() did meaningful work before this change.

## Which versions are affected by CVE-2026-80651?


## How do I fix CVE-2026-80651?

Apply the vendor's patch.

## Is CVE-2026-80651 being exploited?

There is no known exploitation of CVE-2026-80651 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80651 and fix it if it is affected.

What it is: CVE-2026-80651 is a vulnerability in Linux, published on 28 Aug 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-2026-80651 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-2026-80651/ (Markdown: https://insights.sbomify.com/CVE-2026-80651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80651
- OSV: https://osv.dev/vulnerability/CVE-2026-80651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80651/
Summaries are generated and may contain mistakes; the official description above is the record.