# CVE-2026-64307: crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)

> A local attacker can crash the host system by triggering a specific ioctl path when SEV initialization fails, affecting Linux kernel users with AMD SEV enabled.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-64307, DEBIAN-CVE-2026-64307, GHSA-wv9v-6465-83fw, ROOT-OS-UBUNTU-2204-CVE-2026-64307, UBUNTU-CVE-2026-64307

## What is CVE-2026-64307?

CVE-2026-64307 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Jul 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 - Do not initialize SNP for ioctl(SNP_CONFIG)

Sashiko notes:

> if SEV initialization fails and KVM is actively running normal VMs, could a
> userspace process trigger this code path via /dev/sev ioctls (e.g.,
> SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN
> execution for an active VM trigger a general protection fault and crash the
> host?

Refuse to re-try initialization if SNP is not already initialized for
SNP_CONFIG.

This is technically an ABI break: before if SNP initialization failed it
could be transparently retriggered by this ioctl, and if no VMs were
running, everything worked fine. Hopefully this is enough of a corner case
that nobody will notice, but someone does, there are a few options:

* do something like symbol_get() for kvm and refuse to initialize if KVM is
  loaded
* check each cpu's HSAVE_PA for non-zero data before re-initializing
* once initialization has failed, continue to refuse to initialize until
  the ccp module is unloaded

## Which versions are affected by CVE-2026-64307?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64307?

Apply the vendor's patch.

## Is CVE-2026-64307 being exploited?

There is no known exploitation of CVE-2026-64307 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64307 and fix it if it is affected.

What it is: CVE-2026-64307 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Jul 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-2026-64307 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-64307/ (Markdown: https://insights.sbomify.com/CVE-2026-64307/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64307
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64307
- OSV: https://osv.dev/vulnerability/CVE-2026-64307

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64307/
Summaries are generated and may contain mistakes; the official description above is the record.